A Study on the Influence of Intake Geometry on the Turbocharger Compressor Performance

2018 ◽  
Author(s):  
Dhinagaran Ramachandran ◽  
Sreenivasa Somashekarappa ◽  
Balamurugan Mayandi ◽  
Ranganathan Reddy Shanmugam ◽  
Saravanan Boolingam ◽  
...  
Keyword(s):  
Total Pressure ◽  
Combustion Engine ◽  
Fluid Dynamic ◽  
Cfd Simulations ◽  
Pressure Losses ◽  
Inlet Distortion ◽  
Compressor Performance ◽  
Compressor Map ◽  
Compressor Efficiency ◽  
Insight Into

Increasing demands on the improvement of the performance of the turbocharged internal combustion engine places in turn higher demands on the efficiency of turbochargers. The aerodynamic performance of the turbocharger compressor is influenced by the uniformity of airflow that the impeller receives. Typically, the compressor performance is measured in a gas stand with straight and conical adaptors. The ducting before the compressor in a vehicle is invariably more complex with additional bends than in the gas stand test setup. This creates differences in performance of engine compared to the performance based on the compressor map obtained from the gas stand. In this study, Computational Fluid Dynamic (CFD) simulations are performed for a compressor with a baseline intake that has a single bend and the results are compared with the test data. Subsequently tests and CFD simulations are performed with ducts having additional bends. The CFD results provide insight into the losses arising in the intake. Additional bends and the nature of bends add to total pressure losses and distorts the flow going into the impeller. The inlet distortion and total pressure losses are quantitatively expressed in terms of a set of parameters in order to facilitate comparison of different designs. The intake geometry is modified to improve the overall compressor efficiency by reducing pressure drop and inlet distortion.

Heat Transfer on a Turbocharger Under Constant Load Points

2009 ◽  
Author(s):  
A. Romagnoli ◽  
Ricardo Martinez-Botas
Keyword(s):  
Heat Transfer ◽  
Combustion Engine ◽  
Constant Load ◽  
Heat Transfer Process ◽  
Transfer Model ◽  
Performance Deterioration ◽  
Exit Temperature ◽  
Standard Set ◽  
Compressor Performance ◽  
Compressor Efficiency

The processes occurring in turbo machinery applications are frequently treated as adiabatic. However, in a turbocharger significant heat transfer occurs, leading to a deficit of turbocharger performance. The overall objective of this experimental work is to improve the understanding of the heat transfer process taking place in a turbocharger when installed on an internal combustion engine. In order to do this, beyond the standard set of measurements needed to define the turbo operating point, a large number of thermocouples were installed on the turbocharger. The tests results allow the quantification of the temperatures within the turbocharger and revealed that a nonuniform temperature distribution exists on the compressor and turbine casings. This is partly attributed to the proximity of the turbocharger to the engine. This process plays a role on the deterioration of the compressor efficiency when compared to the corresponding adiabatic efficiency. A correlation that allows the calculation of the compressor exit temperature is proposed. The method uses the surface temperature of the bearing housing; it was validated against experimental data with deviations no larger than 3%. A simplified 1-dimensional heat transfer model was also developed and compared with experimental measurements. The algorithms calculate the heat transferred through the turbocharger, from the hot end to the cold end by means of lump masses. The compressor performance deterioration from the adiabatic map is predicted.

Experimental and Numerical Investigations of the Solidity Effect on a Linear Compressor Cascade

2015 ◽  
Author(s):  
J. Sans ◽  
J.-F. Brouckaert ◽  
S. Hiernaux
Keyword(s):  
Total Pressure ◽  
High Speed ◽  
Diffusion Profile ◽  
Compressor Cascade ◽  
Pressure Losses ◽  
Controlled Diffusion ◽  
Numerical Predictions ◽  
Compressor Performance ◽  
Linear Compressor Cascade

The solidity in a compressor is defined as the ratio of the aerodynamic chord over the peripheral distance between two adjacent blades, the pitch. The choice of this parameter represents a crucial step in the whole design process. Most of the studies addressing this issue are based on low-speed compressor cascade correlations. In that prospect, aiming at updating those correlation data as well as improving the physical understanding of the solidity effect on compressor performance, both experimental and numerical high-speed cascade investigations have been carried out at the von Karman Institute. The profile is a state-of-the-art controlled diffusion blade, representative of a low pressure compressor stator mid-span profile. The performance in terms of total pressure losses and deviation have been measured in the high-speed C3 cascade facility for three different solidities at six incidences and two Mach numbers. Based on the experimental results, a numerical linear cascade model has been built and computations have been run with FINE/Turbo at the same conditions as the measurements. The quality of the numerical predictions is discussed over the whole incidence range and, in particular, big discrepancies are highlighted at off-design incidences. Focusing on the solidity effects at mid-span, both experimental and numerical results are compared with existing correlations. The establishment of updated correlations for such controlled diffusion profile is addressed for both deviation and total pressure losses and at both optimum and off-design conditions.

scholarly journals A Computational Fluid Dynamic Study of Developed Parallel Stations for Primary Fans

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1607
Author(s):  
Juan Pablo Hurtado ◽  
Gabriel Reyes ◽  
Juan Pablo Vargas ◽  
Enrique Acuña
Keyword(s):  
Computational Fluid Dynamic ◽  
Energy Cost ◽  
Fluid Dynamic ◽  
Shock Pressure ◽  
Cfd Model ◽  
Blade Angle ◽  
Cfd Simulations ◽  
Pressure Losses ◽  
Operating Points ◽  
Over Time

A Computational fluid dynamic (CFD) model was developed considering three geometries for primary parallel fan stations that have already been developed, implemented, and are currently in operation within Chilean mines. To standardize the comparison, the same primary fan was used in all the simulations with a unique set of settings (speed, blade angle, and density). The CFD representation was used to determine the operating point per configuration and compare the performances in terms of airflow and pressure delivered. This approach allowed ranking primary fan station geometry based on resistance curve and energy consumption of the fan. This paper presents the results obtained through the CFD simulations and the corresponding primary fans operating points of each configuration: symmetrical branches (SB), overlap branches (OB), and run around (RA) bypass. The RA configuration was identified as the best-performing station geometry on the lowest frictional and shock pressure losses, highest airflow delivery, and lowest energy cost. The results are discussed, considering pressure, velocity, and vector contours to understand the fluid dynamics phenomena occurring inside the station. The capital cost involved in the development of each primary parallel station was considered in the analysis in addition to the energy cost to determine the economic configuration over time.

Analysis of Radial Compressor Performance at Low Pressure Ratios and Compressor Choke

2020 ◽  
Vol 142 (7) ◽  
Author(s):  
Adrian Schloßhauer ◽  
Felix Falke ◽  
Johannes Klütsch ◽  
Iris Kreienborg ◽  
Stefan Pischinger
Keyword(s):  
Pressure Ratio ◽  
Three Dimensional ◽  
Measurement Data ◽  
Low Pressure ◽  
Cfd Simulations ◽  
Process Simulations ◽  
Mass Flowrate ◽  
Compressor Performance ◽  
Compressor Map ◽  
Operating Points

Abstract Strong transient engine load steps can result in low pressure ratio (ΠC) compressor operation for single stage turbocharged (TC) systems. For conventional full load TC engine matching using one-dimensional (1D)-engine process simulation, these operating points are of limited relevance and are consequently less studied. However, for the layout of sequential turbocharging systems, low pressure ratio compressor operation has to be thoroughly understood. Therefore, in this paper, three-dimensional (3D)-computational fluid dynamics (CFD) simulations will be presented, which analyze the stationary compressor behavior at low pressure ratios. Operating points at ΠC<1 are investigated by reducing the compressor outlet pressure. The simulation results are validated against measurement data acquired at a stationary hot gas test bench. The compressor performance is quantified by a corrected compressor torque. Opposed to the well-known operation at ΠC>1, the compressor generates power close to zero speed for ΠC<1 (turbine operation). At higher mass flowrates and ΠC<1, the compressor consumes power. Pressure build-up in the wheel is overcompensated by losses in the diffusor and the volute resulting in a net pressure drop across the stage. The 3D-CFD simulations also allow a speed-dependent evaluation of the choking cross section inside the compressor. At low circumferential speeds, compressor choke occurs in the volute or at the wheel outlet. At higher speeds, choking is observed at the wheel inlet. This behavior must be accounted for compressor map extrapolation methods for 1D-engine process simulations in order to correctly predict the choking mass flowrate.

Numerical Investigation of the Return Channel of a High-Flow Centrifugal Compressor Stage

2015 ◽  
Author(s):  
Holger Franz ◽  
Christoph Rube ◽  
Matthias Wedeking ◽  
Peter Jeschke
Keyword(s):  
Detailed Analysis ◽  
Centrifugal Compressor ◽  
High Flow ◽  
Compressor Stage ◽  
Test Rig ◽  
Cfd Simulations ◽  
Flow Phenomena ◽  
Compressor Performance ◽  
Return Channel ◽  
Insight Into

Steady-state simulations of a high-flow centrifugal compressor stage with return channel for industrial applications are carried out to determine the flow conditions in a new compressor test rig at the RWTH Aachen University. Overall performance predictions, conducted by means of CFD simulations, will be shown and discussed in this paper. Furthermore, a detailed analysis of the stage components is presented, providing an insight into the flow phenomena responsible for the compressor performance. Thereby, the analysis focuses on the return channel. The compressor has a shrouded impeller with 3D-twisted blades, operating at a high flow coefficient and moderate pressure ratios, as usual for multistage single-shaft compressors. The complete computational domain consists of an inlet duct, the impeller, a vaneless diffuser and return channel with bends to guide the flow. All CFD simulations have been carried out in advance of the test rig construction. The results of the simulations have been used to define the measurement locations within the test rig. Within this paper, the predicted flow phenomena in the return channel, which are strongly three-dimensional, are detailed and analyzed against the backdrop of their origin and their contribution to the overall losses. Furthermore, the available measurement results of the overall compressor performance are compared to the numerical simulations to validate the numerical setup. The objective of this paper is to give a detailed analysis of the flow in the return channel of a new compressor test rig built up at the Institute of Jet Propulsion and Turbomachinery of the RWTH Aachen University. The investigation is conducted to get an insight into the formation processes of the dominant flow phenomena affecting the overall stage performance. These investigations can form the basis for developing new strategies for return channel improvements.

Investigation of the Effects of Inlet Swirl on Compressor Performance and Operability Using a Modified Parallel Compressor Model

2011 ◽  
Author(s):  
Nicholas Fredrick ◽  
Milt Davis
Keyword(s):  
Experimental Data ◽  
Total Pressure ◽  
Engine Performance ◽  
Propulsion System ◽  
Turbine Engine ◽  
Turbofan Engines ◽  
Inlet Distortion ◽  
Inlet Swirl ◽  
Engine Compressor ◽  
Compressor Performance

Serpentine ducts used by both military and commercial aircraft can generate significant flow angularity and total pressure distortion at the engine face. Most low by-pass ratio turbofan engines with mixed exhaust are equipped with inlet guide vanes (IGV) which can reduce the effect of moderate inlet distortion. High by-pass ratio and some low by-pass ratio turbofan engines are not equipped with IGVs, and swirl can in effect change the angle of attack of the fan blades. Swirl and total pressure distortion at the engine inlet will impact engine performance, operability, and durability. The impact on the engine performance and operability must be quantified to ensure safe operation of the aircraft and propulsion system. Testing is performed at a limited number of discrete points inside the propulsion system flight envelope where it is believed the engine is most sensitive to the inlet distortion in order to quantify these effects. Turbine engine compressor models are based on the limited amount of experimental data collected during testing. These models can be used as an analysis tool to improve the effectiveness of engine testing and to improve understanding of engine response to inlet distortion. The Dynamic Turbine Engine Compressor Code (DYNTECC) utilizes parallel compressor theory and quasi-one-dimensional Euler equations to determine compressor performance. In its standard form, DYNTECC uses user supplied characteristic stage maps in order to calculate stage forces and shaft work for use in the momentum and energy equations. These maps were typically developed using experimental data or created using characteristic codes such as the 1-D Mean Line Code (MLC) or the 2-D Streamline Curvature Code. The MLC was created to calculate the performance of individual compressor stages and requires less computational effort than the 2-D and 3-D models. To improve efficiency and accuracy, the MLC has been incorporated into DYNTECC as a subroutine. Rather than independently developing stage maps using the MLC and then importing these maps into DYNTECC, DYNTECC can now use the MLC to develop the required stage characteristic for the desired operating point. This will reduce time and complexity required to analyze the effects of inlet swirl on compressor performance. The combined DYNTECC/MLC was used in the past to model total pressure distortion. This paper presents the result obtained using the combined DYNTECC/MLC to model the effects of various types of inlet swirl on F109 fan performance and operability for the first time.

Experimental Investigation of Non-Axisymmetrical Flow Control in a Low Speed Axial Compressor

2009 ◽  
Author(s):  
Huabing Jiang ◽  
Yajun Lu ◽  
Wei Yuan ◽  
Qiushi Li
Keyword(s):  
Flow Field ◽  
Flow Control ◽  
Total Pressure ◽  
Pressure Rise ◽  
Separated Flow ◽  
Experimental Results ◽  
Stall Margin ◽  
Casing Treatment ◽  
Compressor Performance ◽  
Compressor Efficiency

The non-axisymmetric feature of the compressor separated flow field should be considered when flow control technology is utilized to improve compressor performance. An experiment is performed to investigate the effectiveness of non-axisymmetric flow control using arc curve skewed slot casing treatment in the paper. A simplified non-axisymmetric excitation model is presented with variable circumferential excitation extent and location. FFT analysis results indicate that the frequency spectrum of the non-axisymmetric excitation is similar with that of the whole circumferential excitation. The non-axisymmetric excitation possesses the same dominate frequency, smaller amplitude and wider frequency bandwidth compared to the whole circumferential excitation. A simplified circumferential non-axisymmetric arc curve skewed slot casing treatment is utilized to perform non-axisymmetric excitation on the separated flow field of a low speed single stage axial compressor under both uniform and distorted inlet conditions. Experimental results indicate that the non-axisymmetric slotted casing treatment presents strong flow control capability, which could improve compressor efficiency, total pressure rise coefficient and stall margin. For the distorted inlet condition, the stall margin, total pressure rise and efficiency of the compressor are respectively improved by 47.4%, 12.7% and 0.7% compared to the solid casing, and the compressor efficiency is improved by 1.4% compared to the whole circumferential excitation. For uniform inlet condition, the non-axisymmetric excitation can improve compressor efficiency by 1.0% and 1.5% respectively compared to the solid casing and the whole circumferential excitation. The whole circumferential excitation can also improve the compressor total pressure rise coefficient and stall margin, on the contrary, it decreases compressor efficiency. As a result, the non-axisymmetric slotted casing treatment can achieve more excellent compressor performance than the whole circumferential excitation does. Experimental results also indicate that the circumferential extent and location of the non-axisymmetric excitation can influence the effectiveness of the non-axisymmetric excitation. The best compressor performance can be achieved only when the non-axisymmetric excitation is tuned to match the asymmetric compressor separated flow field. Analysis on the experimental results indicates that compressor efficiency improvement achieved with the non-axisymmetric excitation can not simply attribute to the flow loss reduction induced by fewer casing slots. The flow loss reduction within undistorted sector, the circumferential flow exchange and the dynamic response induced by the non-axisymmetric excitation, the unsteady coupling between the non-axisymmetric excitation and the separated flow field might be the key flow factors to influence the compressor flow field structure, and hence influence the compressor performance.

An Investigation Into the Effect of Clearance Aspect Ratio on the Performance of a Variable Geometry Vaned Diffuser for Automotive Turbocharger Application

2020 ◽  
Author(s):  
Lee Gibson ◽  
Stephen Spence ◽  
Sung In Kim ◽  
Charles Stuart ◽  
Martin Schwitzke ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Width Ratio ◽  
Boost Pressure ◽  
Variable Geometry ◽  
Peak Efficiency ◽  
Vaned Diffuser ◽  
Vortical Structures ◽  
Compressor Performance ◽  
Compressor Map ◽  
Compressor Efficiency

Abstract The current state-of-the-art in radial compressor design for automotive turbocharger applications utilize impellers with a high trailing edge backsweep angle and a vaneless diffuser to provide a high boost pressure over a wide operating range. A unique feature of this type of design is that the peak efficiency island is typically located near the choke side of the compressor map. As such, the compressor efficiency is generally satisfactory when the engine is operating at high speed, such as the rated power condition. However, at low speeds the engine operating line is located close to the compressor surge line where the efficiency is generally modest. Thus, there is a need to improve the compressor efficiency at low engine speeds without compromising performance near the choke side of the map or the overall map width. Variable geometry devices have shown good potential to improve the compressor performance without a compromise in map width. In general, variability is achieved by moving walls or rotating vanes to best suit the flow conditions for a given mass flow rate. In order for this to be practically realised, a clearance or gap is required between the stationary and moving parts. This ultimately gives rise to leakage flows within the compressor stage and generally results in a lower achievable efficiency relative to the fixed geometry configuration. A study by the authors on an on/off type variable geometry vaned diffuser identified significant loss mechanisms due to the clearances required for the vanes to slide in to and out of the main flow path. Moreover, the endwall position of the clearance was found to have a marked impact on the compressor stability and peak efficiency. This paper assesses the effect of the clearance depth to width ratio (or aspect ratio) at different endwall positions with the aim of identifying an appropriate geometry and position to approach an optimised design. Steady-state Reynolds-Averaged Navier-Stokes (RANS) simulations were performed using ANSYS CFX at three operating speeds to obtain a broad sense of the effect of the clearance aspect ratio on the compressor performance. It was found that a high value of aspect ratio enabled the formation of large vortical structures in the vaned diffuser. The mixing between the core flow and the vortical structures resulted in significant losses in the vaned diffuser and affected the compressor map width differently depending on the endwall position.

Pressure Losses for Jet Array Impingement With Crossflow

2012 ◽  
Author(s):  
Yeshayahou Levy ◽  
Arvind G. Rao ◽  
V. Erenburg ◽  
V. Sherbaum ◽  
I. Gaissinski ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Numerical Simulations ◽  
Gas Turbines ◽  
Total Pressure ◽  
Turbine Blades ◽  
Jet Impingement ◽  
Solar Panels ◽  
Cfd Simulations ◽  
Pressure Losses

Jet impingement is an efficient heat transfer method and has been used successfully in cooling of turbine blades in gas turbine engines. Although many studies have been conducted on the heat transfer characteristics of jet impingement array, there is a lack of knowledge in pressure drop characteristics of large jet impingement arrays. The pressure losses encountered are becoming increasingly important when applied to micro gas turbines, cooling concentrated solar panels and high density electronic chips. The present work focuses on experimental and theoretical investigation of pressure losses in low Re impingement arrays, 200< Re <3000. Experiments were carried out on jet impingement array with nozzle diameters of 200 to 800 μm. Numerical simulations were also performed with available commercial CFD tools. Reasonable comparisons between experimental results and numerical simulations were obtained. Detailed flow structure, mass flow rate distribution, jet velocity profiles, and pressure drop within the array in the streamwise direction were obtained from the CFD simulations. These simulations enhance the understanding of the physics within multiple jet impingement system. Additionally a semi empirical–analytical method is developed for calculating the total pressure loss within a multi jet impingement system. This simple methodology can provide a quick estimate of the total pressure drop and hence is suited for first order optimization. The methodology is validated by results obtained from experiments and from CFD simulations.

Unsteady Compressor Performance Assessment Using Euler Solvers

2014 ◽  
Author(s):  
Serena Zoppellari ◽  
Vassilios Pachidis
Keyword(s):  
Total Pressure ◽  
Cross Flow ◽  
Complex Flow ◽  
Cfd Simulations ◽  
Computational Overhead ◽  
Numerical Integrator ◽  
Flow Features ◽  
Flow Deviation ◽  
Compressor Performance ◽  
Euler Solver

Although the use of 3D CFD simulations has become common practice, 2D and quasi-3D through-flow tools are still used to quickly assess compressor performance. These tools rely on semi-empirical models and correlations to account for complex flow features such as flow deviation and losses. The purpose of this paper is to describe the methodology that led to the development of FENICE1-PC/2D (Fast Euler Numerical Integrator for Compressor Evaluation). FENICE-PC/2D is an unsteady Euler solver which allows the prediction of complete compressor maps (i.e. forward, stalled and reversed flow). The tool offers the user the choice to run as a 2D flow solver, or as a quasi-2D solver. The latter relies on the principles of the well-established ‘parallel compressors’ technique [1], with cross flow (mass flow exchange between sectors) for the modelling of asymmetric flow fields. In particular, this paper presents the capabilities of both versions of FENICE, highlighting advantages and limitations where appropriate. The tool has been implemented in FORTRAN and verified adopting different compressor geometries. The verification was performed by imposing inlet total pressure and total temperature distortions, to assess the effect of the circumferential mass redistribution on the compressor’s overall performance. For the specific case of total pressure distortion, a comparison against available 3D CFD results was also carried out to verify the circumferential trends of various flow properties. Moreover, the total pressure distortion was used as a trigger to force the C106 compressor into stall and investigate the stall region. The study has showed that both FENICE-PC and FENICE-2D can be used effectively during the compressor preliminary design and development phase to study asymmetric and axisymmetric phenomena, hence avoiding the complexity and computational overhead associated with full 3D CFD simulations.

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