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Rotor Dynamics Analysis Process Essay

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ME 128. Introduction to Mechanical Engineering I. 1 unit

Term Typically Offered: F

Prerequisite: Mechanical Engineering student; first quarter of freshman year.

Introduction to mechanical engineering and its application in professional practice. Includes design, analysis, testing and dissection of mechanical engineering systems, from simple machines to more complicated systems. Introduction to engineering graphic communication. Introduction to HVAC, Manufacturing and Mechatronics concentrations. Includes first quarter cornerstone service learning project. 1 laboratory. Formerly ME 134.

ME 129. Introduction to Mechanical Engineering II. 1 unit

Term Typically Offered: W

Prerequisite: ME 128; Mechanical Engineering student; second quarter of freshman year. Concurrent: ME 163.

Communication of designs for manufacturing using basic definitions of points, lines and planes in space. Pictorials, orthographic projection, section views and auxiliary views. Techniques from geometry and spatial definitions integrated to provide information to both the design and manufacturing processes. 1 laboratory.

ME 130. Introduction to Mechanical Engineering III. 1 unit

Term Typically Offered: SP

Prerequisite: ME 129; Mechanical Engineering student; third quarter of freshman year.

Use of computer-aided design to communicate parts and assemblies. Dimensioned drawings for part fabrication. Introduction to fits and tolerances. Layout drawings and functional assemblies. 1 laboratory.

ME 163. Freshmen Orientation to Mechanical Engineering. 1 unit

Introduction to career opportunities in Mechanical Engineering, exploration of the ethical responsibilities of being a student and professional engineer, and familiarization with the Mechanical Engineering curriculum including cooperative education and international exchange opportunities. Conclusion of cornerstone service learning project. Field trip may be required. 1 activity.

ME 211. Engineering Statics. 3 units

Analysis of forces on engineering structures in equilibrium. Properties of forces, moments, couples, and resultants. Equilibrium conditions, friction, centroids, area moments of inertia. Introduction to mathematical modeling and problem solving. Vector mathematics where appropriate. 3 lectures. Crosslisted as HNRS/ME 211.

ME 212. Engineering Dynamics. 3 units

Analysis of motions of particles and rigid bodies encountered in engineering. Velocity, acceleration, relative motion, work, energy, impulse, and momentum. Further development of mathematical modeling and problem solving. Vector mathematics where appropriate. 3 lectures. Crosslisted as HNRS 214/ME 212.

ME 228. Engineering Design Communication. 2 units

Term Typically Offered: F, W, SP

Use of engineering communication principles to communicate details of project designs including: sketching, orthographic projection, section and auxiliary views, dimensioning, and tolerances. Hand and computer based methods explored. Introduction to design for manufacturability. 2 laboratories.

ME 229. Introduction to Mechanical Engineering for Transfers. 2 units

Term Typically Offered: F, W, SP

Introduction to Mechanical Engineering and its application in professional practice. Includes design, analysis, testing and dissection of mechanical engineering systems. Investigation of personal and professional ethics. Familiarization with the ME curriculum including cooperative education and international exchange opportunities. 1 lecture, 1 laboratory.

ME 234. Philosophy of Design. 3 units

Term Typically Offered: F, W, SP

Prerequisite: Sophomore standing.

General approach to the meaning of engineering design. Conceptual blocks, creativity, design process, design considerations and elements. 3 lectures.

ME 236. Measurement and Engineering Data Analysis. 3 units

Introduction to principles and practice of measurement. Application of probability distributions, sampling, confidence intervals, uncertainty, and regression analysis to engineering experiments and design. Techniques for measuring common physical quantities such as temperature, pressure, and strain. Introduction to laboratory report writing and communication of technical data. 2 lectures, 1 laboratory.

ME 251. Introduction to Detailed Design with Solid Modeling. 2 units

Part and system or assembly design with solid modeling using current software and hardware. Techniques of advanced communication including weld symbols, threaded fasteners, dimensioning and tolerancing. Creation of design layouts and part models with varied configurations and dynamic assembly models. Introduction to section mass and inertia properties. Emphasis of group work and peer review in the production of parts for assemblies. 1 lecture, 1 laboratory.

ME 270. Selected Topics. 1-4 units

Term Typically Offered: TBD

Prerequisite: Open to undergraduate students and consent of instructor.

Directed group study of selected topics. The Schedule of Classes will list title selected. Total credit limited to 8 units. 1 to 4 lectures.

ME 271. Selected Laboratory. 1-2 units

Term Typically Offered: TBD

Prerequisite: Consent of instructor.

Directed group laboratory study of selected topics. The Schedule of Classes will list title selected. Total credit limited to 4 units. 1 to 2 laboratories.

ME 302. Thermodynamics I. 3 units

Properties of working fluids and fundamental relations for processes involving the transfer of energy. First and second laws of thermodynamics, irreversibility and availability. 3 lectures.

ME 303. Thermodynamics II. 3 units

Term Typically Offered: F, W, SP

Prerequisite: ME 302.

Vapor and gas power cycles, refrigeration cycles, thermodynamic relations, psychrometrics, and chemical reactions. 3 lectures.

ME 305. Introduction to Mechatronics. 4 units

Introduction to microcontrollers and assembly language programming. Emphasis on components and techniques for interfacing that are typical of embedded microcontroller applications (A/D conversion, D/A conversion, interrupts, timers, and pulse-width modulation). Laboratory exercises involve real-time interfacing of microcontrollers to external mechanical and/or electromechanical devices. 3 lectures, 1 laboratory.

ME 318. Mechanical Vibrations. 4 units

Free and forced vibration response of single and multiple degree of freedom systems. Experimental studies of the dynamic behavior of structures and machines. Instrumentation methods utilized in field and laboratory. 3 lectures, 1 laboratory.

ME 320. Consumer Energy Guide. 4 units

GE Area F

Term Typically Offered: TBD

Prerequisite: Junior standing; completion of GE Area A with a grade of C- or better; and GE Area B.

Interdisciplinary connection of everyday consumer decisions with energy costs, security, and global warming. Energy consumption by home appliances and automobiles. Methods to reduce the individual 'energy footprint' with renewable energy, purchasing carbon offsets, and behavioral modifications. 4 lectures. Fulfills GE Area F.

ME 323. Everything is Designed: The Invention and Evolution of Products. 4 units

GE Area F

Term Typically Offered: W

Prerequisite: Junior standing and completion of GE Area B.

Investigation of engineering product designs, including social, environmental, and technological influences. Incorporation of engineering design tools to develop a product using creative methods and design methodology. Exploration of creative problem solving methods and barriers to creativity. 4 lectures. Fulfills GE Area F.

ME 326. Intermediate Dynamics. 4 units

Continuation of ME 212. Additional analysis of planar motion of rigid bodies with particular attention to rotating reference frames. Kinematics of linkages, three dimensional dynamics, introduction to numerical methods and dynamic simulation of mechanisms. 3 lectures, 1 activity.

ME 329. Mechanical Systems Design. 4 units

Term Typically Offered: F, W, SP

Prerequisite: ME 328.

Design of mechanical equipment and systems using various machine elements and components such as threaded fasteners, power screws, springs, gears, bearings, clutches, prime movers, etc. Decision modeling based on technical and economic feasibility. 3 lectures, 1 laboratory.

ME 341. Fluid Mechanics I. 3 units

Fluid properties and fluid statics. Euler and Bernoulli equations. Conservation equations; dimensional analysis. Viscous pipe flow. Course may be offered in classroom-based or online format. 3 lectures.

ME 347. Fluid Mechanics II. 4 units

Conservation equations of fluid dynamics. Viscous flow, boundary layer concepts, lift and drag, compressible flow, turbomachinery. Laboratory measurement of turbomachine performance, velocity profiles, boundary layers on surfaces. 3 lectures, 1 laboratory.

ME 350. Heat Transfer. 4 units

Basic principles of heat transfer by conduction and convection. Laboratory experiments to characterize thermodynamic material properties, energy conversion processes, thermodynamic cycles, and performance of heat transfer equipment. Not open to students with credit in ME 343. 3 lectures, 1 laboratory.

ME 359. Fundamentals of HVAC Systems. 4 units

Fundamentals of heating, ventilating and air-conditioning (HVAC) systems, human comfort and indoor air quality, primary and secondary systems and components. 3 lectures, 1 laboratory.

ME 400. Special Problems for Advanced Undergraduates. 1-4 units

Term Typically Offered: F, W, SP

Prerequisite: Consent of instructor.

Individual investigation, research, studies, or surveys of selected problems. Total credit limited to 4 units.

ME 401. Stress Analysis. 4 units

Advanced strength of materials: behavior of disks, plates, and shells. Theory of elasticity. Energy methods. 3 lectures, 1 laboratory.

ME 402. Orthopedic Biomechanics. 4 units

Biomechanical analysis of the musculoskeletal system. Emphasis on the use of statics, dynamics, strength of materials, viscoelasticity, and poroelasticity to analyze the mechanical loads acting on human joints, the mechanical properties of tissues, and the design of artificial joints. 3 lectures, 1 laboratory.

ME 404. Applied Finite Element Analysis. 4 units

Finite element based solutions to engineering problems with an emphasis on elastostatic problems in structural mechanics. The power and pitfalls associated with the finite element method highlighted through practical modeling assignments. Introduces the use of commercial finite element codes. 3 lectures, 1 laboratory. Crosslisted as BMED/CE/ME 404.

ME 405. Mechatronics. 4 units

Microprocessor applications in machine control and product design. Applied electronics. Drive technology; transducers and electromechanical systems. Real-time programming. Mechatronic design methodology. 3 lectures, 1 laboratory.

ME 409. Interdisciplinary Study in Biomechanics. 4 units

Examination of human motion biomechanics. Experimental and analytical methods in motion analysis based on rigid body dynamics. Protocols for protection of human subjects in research. Hypothesis-driven research in interdisciplinary teams, including written proposal development and written/oral communication of results to a scientific audience. 1 lecture, 3 activities. Crosslisted as BMED/KINE/ME 409.

ME 410. Experimental Methods in Mechanical Design I. 4 units

Bonded resistance strain gages for static and dynamic measurements; rosettes, bridge circuits, lead wire effects, special gages. Data acquisition systems, and measurement of displacement, velocity, and acceleration. Photoelastic methods including birefringent coatings. Applications in mechanical design and metrology. 3 lectures, 1 laboratory.

ME 412. Composite Materials Analysis and Design. 4 units

Behavior of unidirectional fiber composites. Properties of short-fiber composites, and orthotropic lamina. Analysis of laminated composites. Strength and hygrothermal behavior of composite materials. Structural optimization. 3 lectures, 1 laboratory.

ME 415. Energy Conversion. 4 units

Engineering aspects of energy sources, conversion and storage. Topics selected from fossil fuel systems, nuclear power, thermoelectric systems, thermionic converters, fuel cells, magnetohydrodynamic generators, and geothermal, tidal, wind and ocean temperature energy conversion systems. 4 lectures.

ME 416. Ground Vehicle Dynamics and Design. 4 units

Design of ground vehicles for directional stability and control. Tire mechanics and their effects on vehicle performance. Simulation of vehicle dynamics using digital computer. Synthesis of steering mechanism and suspension system. 3 lectures, 1 laboratory.

ME 420. Thermal System Design. 4 units

Radiation and combined mode heat transfer. Design of thermal systems. Engineering economics, thermal component sizing, and steady-state simulation techniques applied to the design and performance analysis of thermal systems. Not open to students with credit in ME 440. 3 lectures, 1 laboratory.

ME 422. Mechanical Control Systems. 4 units

Term Typically Offered: F, W, SP

Prerequisite: ME 318.

Modeling and control of physical systems. Design of mechanical, hydraulic and electrical systems using time response, frequency response, state space, and computer simulation. 3 lectures, 1 laboratory.

ME 423. Robotics: Fundamentals and Applications. 4 units

Introduction to robots and their types. Homogeneous transformations. Kinematic equations and their solutions. Motion trajectories, statics, dynamics, and control of robots. Robot programming. Actuators, sensors and vision systems. 3 lectures, 1 laboratory.

ME 428. Senior Design Project I. 2 units

First of three courses taken sequentially in component and system design using real-world problems. Small teams study and apply techniques of the engineering design process including problem definition, concept generation, feasibility studies and decision making. Practice of professional skills including written and oral communication, teaming, project management, societal responsibility and ethics. 2 laboratories.

ME 429. Senior Design Project II. 2 units

Term Typically Offered: F, W, SP

Prerequisite: ME 428.

Continuation of a project begun in ME 428. Activities focused on detail design, analysis and material procurement. 2 laboratories.

ME 430. Senior Design Project III. 2 units

Term Typically Offered: F, W, SP

Prerequisite: ME 429.

Completion of a project begun in ME 428 and continued in ME 429. Design verified through prototyping and testing. 2 laboratories.

ME 431. Mechanical Design Techniques. 4 units

Comprehensive study of various design methods and techniques. Techniques used to explore various structural concepts such as prestressing, shaping, sizing, etc. Simulation of systems using digital computer. Design criteria identification of design parameters and constraints. 3 lectures, 1 laboratory.

ME 434. Enhanced Oil Recovery. 4 units

Primary, secondary, and tertiary (enhanced) oil recovery methods. Waterflooding, polymerflooding, gas injection, steam injection, in-situ combustion, chemical flooding, miscible flooding. Performance calculations and computer applications in EOR. 4 lectures.

ME 435. Drilling Engineering. 4 units

Theory and practice of oilwell planning, drilling, well logging, and completion applied to the development of new oil and gas production, from onshore and offshore fields. 4 lectures.

ME 436. Petroleum Production Engineering. 4 units

Design and operation of surface and subsurface equipment required in oil production. Processes and systems involved are rod pumping, gas lifting, acidizing, hydraulic fracturing, fluid gathering and storage, separation of oil, gas, water and sediment from produced fluid. Includes equipment used in enhanced oil recovery processes. 4 lectures.

ME 440. Thermal System Design and Optimization. 4 units

Design and optimization of thermal systems. Engineering economics, thermal component sizing, steady-state simulation, and optimization techniques applied to the design and performance analysis of thermal systems. Not open to students with credit in ME 420. 3 lectures, 1 laboratory.

ME 441. Single Track Vehicle Design. 4 units

Design of single track vehicles, including handling characteristics, ergonomics and human power, strength and stiffness considerations, braking and suspension. Laboratory focus on designing a single track vehicle, including fabrication of a handling prototype. 3 lectures, 1 laboratory.

ME 442. Design of Machinery. 4 units

Graphical synthesis and analysis of mechanisms and machines. Analytical fundamentals for study of displacements, velocities, accelerations, and static and dynamic forces necessary for design of planar linkages and gearing systems. Creative design projects using software simulation tools. 3 lectures, 1 laboratory.

ME 443. Turbomachinery. 4 units

Performance characteristics of various types for liquids and for gases. Criteria for proper selection of type and main dimensions. Cavitation criteria. Gas turbine cycles and performance. Two-dimensional cascades. Axial flow turbines and compressors. Centrifugal compressors and radial-inflow turbines. 4 lectures.

ME 444. Combustion Engine Design. 4 units

Application of design parameters to the various engine cycles. Aspects of the combustion processes. Emission regulation effects on engine design. Static and dynamic loading. 3 lectures, 1 laboratory.

ME 450. Solar Thermal Power Systems. 4 units

Term Typically Offered: W

Prerequisite: ME 343. Recommended: ME 415.

High and intermediate temperature systems for conversion of solar energy to mechanical power and heat. Thermal energy storage and total thermal energy system design. 3 lectures, 1 laboratory.

ME 456. HVAC Air and Water Distribution System Design. 4 units

Air and water distribution components and systems and the design of these systems with applications to the heating, ventilating and air-conditioning (HVAC) industry. 3 lectures, 1 laboratory.

ME 457. Refrigeration Principles and Design. 4 units

Basic engineering principles of refrigeration processes including: vapor compression cycles, multipressure systems, absorption systems, steam jet cooling, air cycles, and low temperature refrigeration. 3 lectures, 1 laboratory.

ME 458. Building Heating and Cooling Loads. 4 units

Building heating and cooling load calculations, estimating energy consumption and operating costs for heating, ventilating and air-conditioning system design and selection. 3 lectures, 1 laboratory.

ME 459. HVAC Senior Design Project I. 3 units

First quarter of a two quarter sequence. Team project work in designing heating, ventilating and air-conditioning (HVAC) systems. New developments, policies and practices in the HVAC industry. Professional ethics relevant for practicing engineers. 1 lecture, 2 laboratories.

ME 460. HVAC Senior Design Project II. 2 units

Continuation of work begun in ME 459. Team project designing heating, ventilating and air-conditioning (HVAC) systems. 2 laboratories.

ME 470. Selected Advanced Topics. 1-4 units

Term Typically Offered: TBD

Prerequisite: Consent of instructor.

Directed group study of selected topics for advanced students. Open to undergraduate and graduate students. The Schedule of Classes will list title selected. Total credit limited to 12 units. 1 to 4 lectures.

ME 471. Selected Advanced Laboratory. 1-4 units

Term Typically Offered: TBD

Prerequisite: Consent of instructor.

Directed group laboratory study of selected topics for advanced students. Open to undergraduate and graduate students. The Schedule of Classes will list title selected. Total credit limited to 8 units. 1 to 4 laboratories.

ME 488. Wind Energy Engineering. 4 units

Engineering aspects of windpower systems including mechanical design, support structure design, aerodynamic analysis, wind field analysis, system concepts and analysis, and economics. 4 lectures.

ME 493. Cooperative Education Experience. 2 units

CR/NC

Term Typically Offered: F, W, SP

Prerequisite: Sophomore standing and consent of instructor.

Part-time work experience in business, industry, government, and other areas of student career interest. Positions are paid and usually require relocation and registration in course for two consecutive quarters. Formal report and evaluation by work supervisor required. Credit/No Credit grading only. No major credit allowed; total credit limited to 6 units.

ME 494. Cooperative Education Experience. 6 units

CR/NC

Term Typically Offered: F, W, SP

Prerequisite: Sophomore standing and consent of instructor.

Full-time work experience in business, industry, government, and other areas of student career interest. Positions are paid and usually require relocation and registration in course for two consecutive quarters. Formal report and evaluation by work supervisor required. Credit/No Credit grading only. No major credit allowed; total credit limited to 18 units.

ME 495. Cooperative Education Experience. 12 units

CR/NC

Term Typically Offered: F, W, SP

Prerequisite: Sophomore standing and consent of instructor.

Full-time work experience in business, industry, government, and other areas of student career interest. Positions are paid and usually require relocation and registration in course for two consecutive quarters. A more fully developed formal report and evaluation by work supervisor required. Credit/No Credit grading only. No major credit allowed; total credit limited to 24 units.

ME 500. Individual Study. 1-3 units

Term Typically Offered: F, W, SP

Prerequisite: Consent of department head, graduate advisor and supervising faculty member.

Advanced study planned and completed under the direction of a member of the department faculty. Open only to graduate students who have demonstrated ability to do independent work. Enrollment by petition.

ME 501. Continuum Mechanics and Elasticity. 4 units

Term Typically Offered: TBD

Prerequisite: Graduate standing.

Introduction to continuum mechanics. Kinematics, stress, and balance laws. Constitutive theory for isotropic and anisotropic solids and viscous fluids. Applications including design of beams and pressure vessels, stress concentrations, fiber-reinforced composites, and non-homogeneous biological materials. 4 lectures. Crosslisted as CE 511/ME 501.

ME 503. Inelastic Stress Analysis. 4 units

Perfectly plastic and work hardening materials; von Mises and Tresca yield, isotropic and kinematic hardening flow rules, boundary-value problems. Finite elasticity: kinematics, Cauchy- and Green-elasticity, invariance, constraints, Neo-Hookean and Mooney-Rivlin materials, experimental approaches, non-uniqueness, anisotropy, residual stress, thermoelasticity, boundary-value problems. 4 lectures. Crosslisted as CE 513/ME 503.

ME 504. Finite Element Analysis. 4 units

Linear finite element theory and analysis. Strong, weak and variational formulations. Physical and isoparametric spaces. Error estimates and numerical integration. Development of finite element algorithms. Use of commercial finite element codes to illustrate course concepts including modeling issues and limitations. 3 lectures, 1 laboratory. Crosslisted as CE/ME 504.

ME 506. System Dynamics. 4 units

Term Typically Offered: SP

Prerequisite: Graduate standing or consent of instructor.

Unified approach for mathematical modeling and analysis of dynamic physical systems which may store energy in multiple energy domains. Emphasis on developing lumped-parameter linear system models from a set of primitive elements in a systematic manner. 4 lectures.

ME 507. Mechanical Control System Design. 4 units

Term Typically Offered: F

Prerequisite: Graduate standing or consent of instructor.

Application of principles of high-level design to mechanical control system implementation. Use of modified state transition logic in conjunction with object-oriented programming as design methodology. Real-time programming using above techniques for control of mechanical systems. 3 lectures, 1 laboratory.

ME 517. Advanced Vibrations. 4 units

Term Typically Offered: SP

Prerequisite: ME 318, graduate standing or consent of instructor.

Vibration of complex engineering systems. Inertia and stiffness matrices. Natural frequencies and normal modes. Approximate solutions and computer techniques. Response to transient and periodic inputs. 3 lectures, 1 laboratory.

ME 518. Machinery Vibration and Rotor Dynamics. 4 units

Term Typically Offered: W

Prerequisite: ME 318, graduate standing or consent of instructor.

Vibrations relating to rotating machinery. Modeling of structural rotordynamic phenomena induced by shaft flexibility, bearings, and seals. Laboratory measurement of rotor system dynamic response and interpretation of machinery diagnostic information. Research project on a related topic. 3 lectures, 1 laboratory.

ME 540. Viscous Flow. 4 units

Introduction to tensor calculus and indicial notation. Development of Reynolds' Transport Theory. Special forms of the governing equations of fluid motion. Internal flows and other classical solutions to the Navier-Stokes equations. 4 lectures.

ME 541. Advanced Thermodynamics. 4 units

Selected modern applications of thermodynamics which may include topics from: 1) equilibrium and kinetics as applied to combustion and air pollution, analysis and evaluation of techniques used to predict properties of gases and liquids, and 2) improvement of modern thermodynamic cycles by second law analysis. 4 lectures.

ME 542. Dynamics and Thermodynamics of Compressible Flow. 4 units

Control volume analysis of fluid-thermo equations for one-dimensional, compressible flow involving area change, normal shocks, friction, and heat transfer. Two-dimensional supersonic flow including linearization, method of characteristics, and oblique shocks. One-dimensional constant area, unsteady flow, 4 lectures.

ME 552. Advanced Heat Transfer I. 4 units

Advanced principles of heat transfer. Classical solution techniques to problems in conduction and/or radiation. 4 lectures.

ME 553. Advanced Heat Transfer II. 4 units

Advanced principles of heat transfer. Classical solution techniques to problems in convection. 4 lectures.

ME 554. Computational Heat Transfer. 4 units

Numerical solutions of classical, industrial, and experimental problems in conduction, convection, and radiation heat transfer. 3 lectures, 1 laboratory.

ME 556. Advanced Heat Transfer III. 4 units

Advanced principles of heat transfer. Classical solution techniques to problems in radiation with applications related to the role of radiation heat transfer in the development of fire in buildings. 4 lectures. Crosslisted as FPE/ME 556.

ME 563. Graduate Seminar. 1 unit

Term Typically Offered: W

Prerequisite: Graduate standing in mechanical engineering program.

Current developments in mechanical engineering. Participation by graduate students, faculty and guests. 1 seminar.

ME 570. Selected Advanced Topics. 1-4 units

Term Typically Offered: TBD

Prerequisite: Graduate standing or consent of instructor.

Directed group study of selected topics for advanced students. The Schedule of Classes will list topic selected. Total credit limited to 8 units; may be repeated in same term. 1-4 seminars.

ME 571. Selected Advanced Laboratory. 1-4 units

Term Typically Offered: TBD

Prerequisite: Graduate standing of consent of instructor.

Directed group laboratory study of selected topics for advanced students. The Schedule of Classes will list topic selected. Total credit limited to 8 units; may be repeated in same term. 1-4 laboratories.

ME 579. Fluid Power Control. 4 units

Design, analysis, and control of fluid power systems. Analysis of fluid power system components such as valves, actuators, pumps and motors. System response and stability. Dynamic modeling and computer simulation 3 lectures, 1 laboratory.

ME 599. Design Project (Thesis). 1-9 units

Term Typically Offered: F, W, SP

Prerequisite: Graduate standing.

Each individual or group will be assigned a project for solution under faculty supervision as a requirement for the master's degree, culminating in a written report/thesis.

1. Introduction

The continuing demand for reducing CO2 emissions and fuel consumption of internal combustion engines (ICE) is associated with downsizing in combination with high specific power in recent years. The engine displacement or the numbers of cylinders are reduced and an increase in specific power is achieved through a boosting device. Boosted downsized engines with direct injection (DI) technology provide improved efficiency and can achieve 10–15% fuel efficiency benefits compared to natural aspirated engines with equal power output (Golloch [1], Weinowski et al. [2]). Usually, exhaust-gas turbochargers are used as an efficient charging concept in ICE.

Due to the high number of turbocharged engines in the market, the continuous improvement of the turbochargers (TC) performance is of major interest in development. On the one hand, special attention is given to improve the aerodynamic efficiency (e.g., variable nozzle TC (O’Conner and Smith [3]) or twin scroll turbines (Lückmann et al. [4]); on the other hand there are intensive research activities in the field of the turbocharger bearing systems and their resulting mechanical losses. In [5,6] it was shown that there is still significant potential for increasing effective turbine efficiencies, especially in the context of mechanical losses. Friction losses of the TC affect the minimum engine speed, from where the desired low-end torque (LET) can be achieved. The transient performance of the engine is significantly influenced. Furthermore, the part-load fuel consumption of Diesel engines can be decreased with reduced TC friction. Due to high rotational speeds (up to 300,000 1/min in common automotive turbochargers) and high thrust loads of up to ±150 N depending on the operating condition (Uhlmann [7]), hydrodynamic bearings are the predominant bearing technology. Rotor systems with hydrodynamic bearings show non-linear motion behavior with synchronous unbalanced vibrations and subharmonic phenomena (oil whirl and oil whip, see e.g., [8,9,10,11,12]). To ensure safe operation, these effects must be attenuated as much as possible. Therefore, hydrodynamic (semi-/full-) floating ring bearings with a coupled inner and outer oil film are applied as they offer a better damping behavior than single film bearings. Since the non-linear motion behavior influences the mechanical losses arising from the bearing system, it is important to consider the entire turbocharging system at an early stage of development.

An elastic multi-body simulation (EMBS) coupled with finite element method (FEM) calculations for the simultaneous solution of the non-linear hydrodynamic lubricating film pressures (and reaction forces) is currently the most efficient and accurate method for this kind of analysis, see e.g., these studies [10,13,14,15]. Most publications focus on the vibrations occurring during a speed ramp-up. In the present paper the authors measured the bearing friction of a common automotive turbocharger for three different oil inlet temperatures on a dedicated component test bench customized for turbocharger bearing friction analysis. Additionally, hot gas test bench measurements were carried out to capture the shaft motion of this turbocharger. EMBS simulations (for structural dynamics of the flexible shaft and mounted components) and fully-coupled simultaneous FE evaluation of the Reynolds lubrication equation (for the hydrodynamic analysis of the bearing oil films) with both test bench conditions are carried out to validate the simulation model. In a last step, parameter variations of the unbalanced masses and the unbalance phase of compressor and turbine wheel, as well as of the wheel sizes are carried out to answer the following questions:
  • Compressor and turbine wheels are removed to neglect aerodynamic losses at the friction test bench. Are the bearing friction measurements on the friction test bench transferable to the bearing behavior of the hot gas test bench with complete rotor assembly?

  • How much do the non-linear rotor dynamics influence the resulting friction?

  • Are the mechanical losses dependent on balance quality and/or wheel sizes?

2. Methodology

In the following Section, a detailed description of the tested turbocharger, the experimental investigations as well as of the simulation model is given.

2.1. Examined Turbocharger

The investigated turbocharger is a common variable nozzle turbocharger (VNT) with semi-floating bearings for Diesel engines which is in series production of different light duty and passenger vehicles. The geometry was 3D scanned and CAD data were re-generated to use the detailed geometry for the simulation model. To validate the 3D CAD data and material (density) the rotational inertia for compressor wheel, turbine and shaft was measured on a pendulum type test bench by determining the oscillation period and compared to the computational model using Equations (1) and (2). Figure 1 shows the pendulum test bench and a schematic view of it.
  • = period time of one oscillation

  • = mass of the rotor assembly

  • = distance from rotational axis to strings attachment to the rotor

  • = string length

  • = gravity

  • = inertia

The turbocharger has a compressor exducer diameter of , a turbine inducer diameter of and a total assembly length of . The effective shaft diameter at the journal bearing is 7.9 mm. The measured masses and rotational inertias can be found in Table 1.

The bearing system consists of a semi-floating journal bearing, where the rotational movement is fixed. For that, an anti-rotation pin is used on the compressor side of the bearing. Such a bearing type can be seen in Figure 6. Additionally, an axial movement of the bearing is not possible due to a centered fixation pin in the middle of the semi-floating ring. In order to support the turbocharger in axial direction, a segment pad thrust bearing is used with symmetrical design on compressor/turbine side. Main dimensions of the bearing system can be found in Table 2 below.

2.2. Experimental Investigations

For the experimental investigations two different methods were used. First, the examined turbocharger is set-up on a friction test bench which was specially designed to quantify the friction losses of TC bearings. In a second step, the shaft motion for the same turbocharger was measured on a hot gas test bench to obtain validation data for the simulation model.

2.2.1. Turbocharger Friction Test Bench

In this section the experimental setup is described that was used to obtain the bearing friction loss. The rotor of the turbocharger is driven by a high speed electric engine which itself is supported by electro-magnetic bearings, thus enabling operating speeds of up to nTC = 140,000 1/min. Friction losses Pf of the turbocharger bearings are determined through direct torque measurement (Mf) between the electric drive motor and the turbocharger bearings:

The torque sensor used in this application features a measurement range of 100 N mm. The thrust bearing of the turbocharger can be loaded with thrust forces of up to Fax = 100 N in either positive (“pulling of turbine”) or negative (“pulling of compressor”) direction by using a magnetic linear actuator. The thrust load can be controlled independently of the operating speed. The electric drive motor and the TC rotor are connected through a pin joint coupling, which allows to transmit thrust forces from the linear actuator onto the TC bearing. In order to eliminate any aerodynamic drag, the rotor wheels are removed from the shaft. Hence, the measured drag torque is resulting purely from the friction losses generated within the bearing system (neglecting negligible windage losses on the shaft surface). Special care is taken to ensure precise alignment between the electric motor shaft and the turbocharger rotor shaft. Temperature and pressure of the oil feeding the bearing are controlled by using a conditioning unit. The feed temperature can be varied ranging from 40 °C up to 120 °C, whereas the (absolute) feed pressure can be controlled between 1 bar and 6 bar. The oil is discharged into ambient conditions at the outlet of the bearing housing. Standard 5W30 synthetic oil is used for the present measurement. The test bench setup is shown schematically in Figure 2.

2.2.2. Hot Gas Turbocharger Test Bench

In addition to the measurements on the friction tests bench, the turbocharger has also been operated on a hot gas turbocharger test bench. The overall setup is highlighted in Figure 3. In this particular case the energy to drive the turbine is provided by a natural gas burner which is installed upstream of the turbine housing. A specially machined measurement pipe is installed upstream and downstream of the turbine housing in order to quantify its specific inlet and outlet conditions in terms of temperature and pressure. The mass flow rate through the turbine is measured upstream of the combustion chamber divided in the fresh dried air and natural gas share. An eddy current speed sensor is installed into the compressor housing to measure the speed of the turbocharger. As the main objective of the hot gas test bench measurements is the quantification of the rotor dynamics during operation, high frequency eddy current sensors are installed close to the compressor nut (see Figure 4). The sensors were calibrated prior to testing on the actual material of the compressor nut to ensure high measurement accuracy. The two sensors were synchronized in order to allow an absolute allocation of the rotor throughout the measurement.

The tests used for the calibration and validation of the multibody simulations (MBS) model mainly consist of a speed variation. Here, the compressor was operated close to its peak efficiency curve. The compressor mass flow rate was controlled through backpressure valves which are installed downstream of the compressor. A total number of 6 operating points were measured in a speed range from 97,000 1/min < nTC < 195,000 1/min as listed in Table 3.

The speed of the turbocharger is changed by adapting the turbine mass flow rate. Each operating point was run under stationary boundary conditions (const. turbine flow rate) and was checked for complete convergence by monitoring the stability of every variable shown in Figure 3

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