Development of Off-Design Turbocharger Modelling Combined with 1-D Engine Model (original) (raw)
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Physical Modeling of Automotive Turbocharger Compressor: Analytical Approach and Validation
SAE Technical Paper Series, 2011
Global warming is a climate phenomenon with worldwide ecological, economic and social impact which calls for strong measures in reducing automotive fuel consumption and thus CO 2 emissions. In this regard, turbocharging and the associated designing of the air path of the engine are key technologies in elaborating more efficient and downsized engines. Engine performance simulation or development, parameterization and testing of model-based air path control strategies require adequate performance maps characterizing the working behavior of turbochargers. The working behavior is typically identified on test rig which is expensive in terms of costs and time required. Hence, the objective of the research project "virtual Exhaust Gas Turbocharger" (vEGTC) is an alternative approach which considers a physical modeled vEGTC to allow a founded prediction of efficiency, pressure rise as well as pressure losses of an arbitrary turbocharger with known geometry. The model is conceived to use smallest possible number of geometry as well as material parameters. Thus, conventional expensive and time-consuming application processes can be countered and test rig as well as in vehicle measurements can be reduced. Furthermore, the vEGTC model enables the prediction of different turbocharger behavior caused by geometry variations. Within this paper it is shown in which way the radial compressor as a representative modeling component can be described by zero-dimensional equations: in order to simulate the working behavior of the compressor the geometry, the thermodynamic state of the inlet-air and the turbocharger speed are assumed to be known. The loss mechanisms are devised using analytical and semi-empirical loss correlations. In order to validate the compressor efficiency the heat transfer from the turbine to the compressor is considered. Finally, the simulation output is compared to manufacturer maps of three different turbochargers pointing out the reliability of the model. Thus, a comprehensive validation of the vEGTC model is yielded. The object-oriented language Modelica is used for modeling and the simulations are provided by the Dymola solver.
Design, Plant Test and CFD Calculation of a Turbocharger for a Low-Speed Engine
Applied Sciences, 2020
Various approaches and techniques are used to design centrifugal compressors. These are engineering one-dimensional and quasi-three-dimensional programs, as well as CFD Computational Fluid Dynamics (CFD) programs. The final judgment about the effectiveness of the design is given by testing the compressor or its model. A centrifugal compressor for an internal combustion engine turbocharger was designed jointly by the Research Laboratory “Gas Dynamics of Turbomachines” of Peter the Great St. Petersburg Polytechnic University (SPbPU) and RPA (Research and Production Association) “Turbotekhnika”. To check its dimensionless characteristics, the compressor was tested with two geometrically similar impellers with a diameter of 175 (TKR 175E) and 140 mm (TKR 140E). The mathematical model of the Universal Modeling Method calculates the efficiency in the design mode for all tests of both compressors with an error of 0.89%, and the efficiency for the entire characteristic with an error of 1.55...
Revista de Engenharia Térmica, 2021
Large internal combustion engines (ICEs) performance is limited by knocking phenomenon due to harsh ambient conditions such as hot temperature and excessive humidity. The performance of these engines can be enhanced by cooling and dehumidifying the inlet air on turbocharger upstream under safe operation conditions through a cooling coil heat exchanger, hence, increasing the power output as well as reducing the brake specific fuel consumption and pollutant specific emissions. Analysis have been performed in the GT-POWER software through a 1-D thermodynamic modelling of the Wärtsilä W20V34SG engine, making it possible to verify the influence of cooled and dehumidified ambient air, considering a temperature range from 9.5°C (282.7 K) to 15.5°C (288.7 K), while keeping 1 bar for pressure and relative humidity of 100%. Furthermore, the brake mean effective pressure (BMEP) has been set from 20 to 23.45 bar with a step of 1.15 bar. Such simulations are aimed to find the maximum air tempera...
SAE International Journal of Engines, 2011
Turbocharging technique will play a fundamental role in the near future not only to improve automotive engine performance, but also to reduce fuel consumption and exhaust emissions both in Spark Ignition and diesel automotive applications. To achieve excellent engine performance for road application, it is necessary to overcome some typical turbocharging drawbacks i.e., low end torque level and transient response. Experimental studies, developed on dedicated test facilities, can supply a lot of information to optimize the engine-turbocharger matching, especially if tests can be extended to the typical engine operating conditions (unsteady flow). Different numerical procedures have been developed at the University of Naples to predict automotive turbocharger compressor performance both under steady and unsteady flow conditions. A classical 1D approach, based on the employment of compressor characteristic maps, was firstly followed. A different and more refined procedure has been recently proposed. The new approach is based on the solution of the 1D unsteady flow within the stationary and rotating channels constituting the compressor device, starting from a reduced set of geometrical data. The refined methodology can be utilized to directly compute the stationary map of the compressor but also to reproduce the unsteady flow behavior of the device. A specialized components test rig (particularly suited to study automotive turbochargers) has been operating since several years at the University of Genoa. The test facility also allows to develop studies under unsteady flow conditions both on single components and subassemblies of engine intake and exhaust circuit. In the paper the results of a preliminary experimental study developed on a turbocharger compressor for gasoline engine application under unsteady flow conditions are presented. Instantaneous inlet and outlet static pressure and mass flow rate are compared with the corresponding numerical data supplied by simulation codes. The numerical results showed a good agreement with experimental data. In addition, the comparison between the classical and the refined procedure results highlighted the potential of the performed unsteady 1D calculation, especially in specific compressor operating conditions. The integration of the experimental activity with the numerical analysis represents a methodology that can be helpfully employed during the design process of internal combustion engine intake systems.
Volume 1: Compressors, Fans and Pumps; Turbines; Heat Transfer; Combustion, Fuels and Emissions, 2017
Modern Internal combustion engines require high pressure ratios to perform efficiently as well as to reduce emissions. For such applications, a centrifugal compressor with high pressure ratio and broader operating range may be employed. The impeller design of such compressors plays a vital role in producing the efficient operation and hence today’s research focus rigorously over its design. The objective of the current investigation is to study the performance of centrifugal compressors based on variation in exit width, eye tip radius and shroud extension. Shroud extension have previously found to generate higher pressure rise at the same time have the least amount of losses. The pressure ratio, power and torque requirement, isentropic efficiency and thermal aspects were the main considerations for the study.
Determination of heat flows inside turbochargers by means of a one dimensional lumped model.pdf
In the present paper, a methodology to calculate the heat fluxes inside a turbocharger from diesel passenger car is presented. The heat transfer phenomenon is solved by using a one dimensional lumped model that takes into account both the heat fluxes between the different turbocharger elements, as well as the heat fluxes between the working fluids and the turbocharger elements. This heat transfer study is supported by the high temperature differences between the working fluids passing through a typical diesel turbocharger. These flows are the hot exhaust gases coming from the diesel engine exhaust passing through the turbine, the fresh air taken by the compressor, and the lubrication oil passing through the housing. The model has been updated to be used with a new generation of passenger car turbochargers using an extra element in the heat transfer phenomenon that is the water cooling circuit. This procedure allows separating the aerodynamic from the heat transfer effects, permitting to study the behavior of compressor and turbine in a separated way.
CFD ANALYSIS OF TURBOCHARGER TURBINE
Downsizing is a trend in engine development that allows better efficiency and ower emissions based on the increase of power output in reduced displacement engines. A natural gas engine for producer gas operation was adopted. The Producer gas fuelled Engines are the upcoming Technology and more friendly to the environment compared to diesel and petrol Engines. There are some issues related to power de-rating from the engine related to the fuel properties. The main cause for the power de-rating is due to the relatively lower heating value of stoichiometric mixture of producer gas and air. This loss in power can be recovered to a much large proportion by Turbocharging. Matching of the correct turbocharger to an engine is of great importance and is vital for successful operation of a Turbocharged engine. It is important to have a Turbine Map for matching the Turbocharger with an engine. The characteristics of the Turbocharger's Turbine from the original manufacturers were not available. In this work an attempt is made to establish the Performance Characteristics and hence the turbine map for a stripped out Holset Turbocharger Turbine to match with a producer gas fuelled engine. KEYWORDS PG Producer Gas, Tin Inlet Temperature, Tout Outlet Temperature, Pin Inlet Pressure, Pout Outlet Pressure, Pr Pressure Ratio.