A Comparison of a Mono, Twin and Double Scroll Turbine for Automotive Applications

2015 ◽  
Author(s):  
Jason Walkingshaw ◽  
Georgios Iosifidis ◽  
Tobias Scheuermann ◽  
Dietmar Filsinger ◽  
Nobuyuki Ikeya
Keyword(s):  
Mass Flow ◽  
Flow Characteristics ◽  
High Mass ◽  
Flow Rates ◽  
Engine Simulation ◽  
Engine Model ◽  
Trade Offs ◽  
Mass Flow Rates ◽  
The Individual ◽  
The Impact

As a means of meeting ever increasing emissions and fuel economy demands car manufacturers are using aggressive engine downsizing. To maintain the power output of the engine turbocharging is typically used. Due to the miss-match of the mass flow characteristics of the engine to the turbocharger, at low engine mass flow rates, the turbocharger can suffer from slow response known as “Turbolag”. Mono-scroll turbines are capable of providing good performance at high mass flow rates and in conjunction with low inertia mixed flow turbines can offer some benefits for transient engine response. With a multi-entry system the individual volute sizing can be matched to the single mass flow pulse from the engine cylinders. The exhaust pulse energy can be better utilised by the turbocharger turbine improving turbocharger response, while the interaction of the engine exhaust pulses can be better avoided, improving the scavenging of the engine. The behaviour of a mono-scroll turbocharger with the engine using engine simulation tools has been well established. What requires further investigation is the comparison with multi-entry turbines. CFD (Computational Fluid Dynamics) has been used to examine the single admission behaviour of a twin and double scroll turbine. Turbocharger gas stand maps of the multi-entry turbines have been measured at full and single admission. This data has been used in a 0D engine model. In addition, the turbine stage has been tested on the engine and a validation of the engine model against the engine test data is presented. Using the validated engine model a comparison has been made to understand the differences in the sizing requirements of the turbine and the interaction of the mono-scroll and multi-entry turbines with the engine. The impact of the different efficiency and mass flow rate trends of the mono and multi-entry turbochargers are discussed and the trade-offs between the design configurations regarding on engine behaviour are investigated.

A Comparison of a Mono-, Twin-, and Double-Scroll Turbine for Automotive Applications

2015 ◽  
Vol 138 (5) ◽  
Author(s):  
Jason Walkingshaw ◽  
Georgios Iosifidis ◽  
Tobias Scheuermann ◽  
Dietmar Filsinger ◽  
Nobuyuki Ikeya
Keyword(s):  
Mass Flow ◽  
Flow Characteristics ◽  
Engine Exhaust ◽  
Simulation Tools ◽  
Engine Simulation ◽  
Engine Model ◽  
Mass Flow Rates ◽  
Single Mass ◽  
The Individual ◽  
The Impact

As a means of meeting ever increasing emissions and fuel economy demands, car manufacturers are using aggressive engine downsizing. To maintain the power output of the engine, turbocharging is typically used. Due to the mismatch of the mass flow characteristics of the engine to the turbocharger, at low engine mass flow rates (MFRs), the turbocharger can suffer from slow response known as “Turbolag.” Mono-scroll turbines are capable of providing good performance at high MFRs and in conjunction with low inertia mixed flow turbines can offer some benefits for transient engine response. With a multi-entry system, the individual volute sizing can be matched to the single mass flow pulse from the engine cylinders. The exhaust pulse energy can be better utilized by the turbocharger turbine improving turbocharger response, while the interaction of the engine exhaust pulses can be better avoided, improving the scavenging of the engine. The behavior of a mono-scroll turbocharger with the engine using engine simulation tools has been well established. What requires further investigation is the comparison with multi-entry turbines. Computational fluid dynamics (CFD) has been used to examine the single-admission behavior of a twin- and double-scroll turbine. Turbocharger gas stand maps of the multi-entry turbines have been measured at full and single admissions. This data have been used in a 0D engine model. In addition, the turbine stage has been tested on the engine, and a validation of the engine model against the engine test data is presented. Using the validated engine model, a comparison has been made to understand the differences in the sizing requirements of the turbine and the interaction of the mono-scroll and multi-entry turbines with the engine. The impact of the different efficiency and MFR trends of the mono and multi-entry turbochargers is discussed, and the tradeoffs between the design configurations regarding on-engine behavior are investigated.

Numerical Investigation of Local Cooling Enhancement Using Pin-Finned Channel With Incremental Impingement

2017 ◽  
Author(s):  
Susheel Singh ◽  
Sumanta Acharya ◽  
Forrest Ames
Keyword(s):  
Aspect Ratio ◽  
Mass Flow ◽  
Cross Flow ◽  
Surface Cooling ◽  
Local Cooling ◽  
Stagnation Region ◽  
Flow Rates ◽  
Pin Fins ◽  
Mass Flow Rates ◽  
The Impact

Flow and heat transfer in a low aspect ratio pin-finned channel, representative of an internally cooled turbine airfoil, is investigated using Large Eddy Simulations (LES). To achieve greater control of surface cooling distribution, a novel approach has been recently proposed in which coolant is injected incrementally through a series of holes located immediately behind a specially designed cutout region downstream of the pin-fins. Sheltering the coolant injection behind the pin-fins avoids the impact of the cross-flow buildup that deflects the impingement jet and isolates the surface from cooling. The longitudinal and transverse spacing of the pin-fins, arranged in a staggered fashion, is X/D = 1.046 and S/D = 1.625, respectively. The aspect ratio (H/D) of pin-fin channel is 0.5. Due to the presence of the sequential jets in the configuration, the local cooling rates can be controlled by controlling the jet-hole diameter which impacts the jet mass flow rate. Hence, four different hole diameters, denoted as Large (L), Medium (M) , Small (S), Petite (P) are tested for impingement holes, and their effects are studied. Several patterns of the hole-size distributions are studied. It is shown that the peak Nusselt number in the stagnation region below the jet correlates directly with the jet-velocity, while downstream the Nusselt numbers correlate with the total mass flow rates or the average channel velocity. The local cooling parameter defined as (Nu/Nu0)(1-ε) correlates with the jet/channel mass flow rates.

scholarly journals Simulation and Modeling of Flow in a Gas Compressor

2015 ◽  
Vol 2015 ◽  
pp. 1-7
Author(s):  
Anna Avramenko ◽  
Alexey Frolov ◽  
Jari Hämäläinen
Keyword(s):  
Steady State ◽  
Mass Flow ◽  
Gas Flow ◽  
Simulation Method ◽  
High Mass ◽  
Ansys Fluent ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
Low Mass ◽  
Flow Through

The presented research demonstrates the results of a series of numerical simulations of gas flow through a single-stage centrifugal compressor with a vaneless diffuser. Numerical results were validated with experiments consisting of eight regimes with different mass flow rates. The steady-state and unsteady simulations were done in ANSYS FLUENT 13.0 and NUMECA FINE/TURBO 8.9.1 for one-period geometry due to periodicity of the problem. First-order discretization is insufficient due to strong dissipation effects. Results obtained with second-order discretization agree with the experiments for the steady-state case in the region of high mass flow rates. In the area of low mass flow rates, nonstationary effects significantly influence the flow leading stationary model to poor prediction. Therefore, the unsteady simulations were performed in the region of low mass flow rates. Results of calculation were compared with experimental data. The numerical simulation method in this paper can be used to predict compressor performance.

An Experimental Study of the Flow of R-407C in an Adiabatic Spiral Capillary Tube

2009 ◽  
Vol 1 (4) ◽  
Author(s):  
M. K. Mittal ◽  
R. Kumar ◽  
A. Gupta
Keyword(s):  
Experimental Data ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Capillary Tube ◽  
Flow Characteristics ◽  
Flow Rates ◽  
Tube Test ◽  
Mass Flow Rates ◽  
R 134A

The objective of this study is to investigate the effect of coiling on the flow characteristics of R-407C in an adiabatic spiral capillary tube. The characteristic coiling parameter for a spiral capillary tube is the coil pitch; hence, the effect of the coil pitch on the mass flow rate of R-407C was studied on several capillary tube test sections. It was observed that the coiling of the capillary tube significantly reduced the mass flow rate of R-407C in the adiabatic spiral capillary tube. In order to quantify the effect of coiling, the experiments were also conducted for straight a capillary tube, and it was observed that the coiling of the capillary tube reduced the mass flow rate in the spiral tube in the range of 9–18% as compared with that in the straight capillary tube. A generalized nondimensional correlation for the prediction of the mass flow rates of various refrigerants was developed for the straight capillary tube on the basis of the experimental data of R-407C of the present study, and the data of R-134a, R-22, and R-410A measured by other researchers. Additionally, a refrigerant-specific correlation for the spiral capillary was also proposed on the basis of the experimental data of R-407C of the present study.

Experimental and Numerical Investigation of Different Rectangular Volute Geometries for Large Radial Compressors

2011 ◽  
Author(s):  
Michael Bartelt ◽  
Thomas Kwitschinski ◽  
Thomas Ceyrowsky ◽  
Daniel Grates ◽  
Joerg R. Seume
Keyword(s):  
Mass Flow ◽  
Pressure Ratio ◽  
High Mass ◽  
Local Flow ◽  
Flow Rates ◽  
Reduced Dimensions ◽  
External Reference ◽  
Mass Flow Rates ◽  
Compressor Map ◽  
Operating Points

Increases on mass flow rates of modern radial process compressors result on larger machine components. In particular, the dimensions of the outlet volutes increase strongly, resulting in disproportionately large machines whose technical feasibility is restricted due to technological and economical reasons. A resulting aim is to design modern radial compressors much more compact, while improving the efficiency and the pressure ratio. Therefore, the present experimental investigation addresses the compressor behaviour for reduced dimensions of rectangular volutes. Furthermore, the experimental setups are numerically modelled and different operating points are simulated with a commercial CFD-Code. A rectangular, external reference volute is equipped with differently shaped blockage-inlays and the global compressor parameters are measured for all variants. Additionally, the pressure and velocity distributions of the local flow field are determined experimentally for varying mass flow ratios at different circumferentially distributed volute layers. The decrease of the volute cross-section results in a reduction of the compressor map width especially at high mass flow rates. Recommendations are given for designing compact volutes of large radial compressors.

scholarly journals Computational study of a radial flow turbine operates under various pulsating flow shapes and amplitudes

2021 ◽  
pp. 1-24
Author(s):  
Ahmed Rezk ◽  
Sidharath Sharma ◽  
S.M. Barrans ◽  
Abul Kalam Hossain ◽  
P. Samuel Lee ◽  
...  
Keyword(s):  
Mass Flow ◽  
Radial Flow ◽  
Pulsating Flow ◽  
Gradual Change ◽  
Maximum Mass ◽  
Flow Rates ◽  
Flow Accumulation ◽  
Wide Range ◽  
Mass Flow Rates ◽  
The Impact

Abstract Radial flow turbines are extensively used in turbocharging technology due to their unique capability of handling a wide range of exhaust gas flow. The pulsating flow nature of the internal combustion engine exhaust gases causes unsteady operation of the turbine stage. This paper presents the impact of the pulsating flow of various characteristics on the performance of a radial flow turbine. A three-dimensional computational fluid dynamic model was coupled with a one-dimensional engine model to study the realistic pulsating flow. Applying square wave pulsating flow showed the highest degree of unsteadiness corresponding to 92.6% maximum mass flow accumulation due to the consecutive sudden changes of the mass flow rates over the entire pulse. Although saw-tooth showed a maximum mass flow accumulation value of 88.9%, the mass flow rates entailed gradual change resulted in the least overall mass flow accumulation over the entire pulse. These two extremes constrained the anticipated performance of the radial flow turbine operates under realistic pulsating flow. Such constraints could develop an operating envelop to predict the performance and optimize radial flow turbines' power extraction under pulsating flow conditions.

Influence of secondary air mass flow rates on gas/particle flow characteristics near the swirl burner region

Energy ◽  
2011 ◽  
Vol 36 (5) ◽  
pp. 3599-3605 ◽  
Author(s):  
Jianping Jing ◽  
Zhengqi Li ◽  
Lin Wang ◽  
Lizhe Chen ◽  
Guohua Yang
Keyword(s):  
Mass Flow ◽  
Flow Characteristics ◽  
Particle Flow ◽  
Swirl Burner ◽  
Flow Rates ◽  
Air Mass ◽  
Mass Flow Rates ◽  
Secondary Air

scholarly journals Applying the Concepts of Efficiency and Effectiveness to Analyze the Influence of the Number of Passes in the Shell and Tubes Condenser Thermal Performance

2021 ◽  
Vol 8 (1) ◽  
pp. F1-F10
Author(s):  
E. Nogueira
Keyword(s):  
Heat Exchanger ◽  
Mass Flow ◽  
Thermal Performance ◽  
High Mass ◽  
Saturated Steam ◽  
Inlet Temperature ◽  
Flow Rates ◽  
Efficiency And Effectiveness ◽  
Mass Flow Rates ◽  
Number Of Passes

The work analyzes the influence of the number of passes in a shell and tubes condenser heat exchanger, with an inlet pressure of R134a refrigerant in the shell equal to 1.2 MPa. The fluid that circulates in the tubes is water or water-based nanofluid with a fraction of aluminum oxide nanoparticles (Al2O3), and the methodology used subdivides the heat exchanger into three distinct regions: the overheated region, the saturated region, and the subcooled region. The main parameters used to analyze the thermal performance of the heat exchanger were efficiency and effectiveness. Efficiency in the superheated steam region is close to 1.0. There is scope for increasing thermal effectiveness, which can be improved with more significant passes in the tube. The saturated steam region process is efficient for lower mass flow rates of the fluid in the tube, but it is ineffective. However, it is highly effective for high mass flow rates. There is ample scope for increasing effectiveness in the subcooled region. Still, the fluid inlet temperature in the pipe and the work refrigerant pressure are the limiting factors for greater heat exchange in the subcooled region.

scholarly journals Experimental and Numerical Investigation the Effect of Grooves Impeller on Rotating Stall of High Speed Blower

2018 ◽  
Vol 8 (04) ◽  
Author(s):  
Muna S. Kassim ◽  
Fouad A. Saleh ◽  
Alaa Th. Aliwi
Keyword(s):  
Numerical Investigation ◽  
Mass Flow ◽  
High Speed ◽  
Static Pressure ◽  
Rotating Stall ◽  
High Mass ◽  
Ansys Fluent ◽  
Flow Rates ◽  
Frontal Wall ◽  
Mass Flow Rates

Experimental and numerical investigation to study the influence of add (one groove and two grooves) to the unshroud impeller onto the rotating stall as well fluctuations of pressure at a high speed blower of centrifugal. Experimental test rig which includes blower of centrifugal, transducer of pressure as well measurement instrumentations are constructed and designed for this study. A data acquisition system (hardware) as well its (software) have been developed into transferring the signal than transducer of pressure to the computer. The experimental work has been implemented through measuring the variation of static pressure as well fluctuation of pressure for two cases of the impeller (with one groove and with two grooves). Static pressure has been taken in different points arranged onto the frontal-wall of a volute casing along one track for two cases of the impeller. This track is angular track about the impeller. The results of experimental show that the fluctuations of pressure for different mass flow rates are nature of non-periodical and the mass flow rates decrease with the fluctuations of pressure increase. Also, the results indicate that the impeller with two grooves show high mass flow rates comparison with the impeller with one groove. Simulation of numerical has been implemented onto blower of centrifugal to analysis both field of flow as well fluctuations of pressure through using ANSYS (FLUENT 15). The simulation of numerical has been carried out through solve the continuity as well momentum equations with the moving reference framework technicality inside a blower. The numerical simulation results show good agreement with the results of experimental.

Time Scale Model for the Prediction of the Onset of Flame Flashback Driven by Combustion Induced Vortex Breakdown (CIVB)

2009 ◽  
Author(s):  
Marco Konle ◽  
Thomas Sattelmayer
Keyword(s):  
Flame Propagation ◽  
Mass Flow ◽  
Time Scale ◽  
Gas Turbines ◽  
Vortex Breakdown ◽  
High Mass ◽  
Recent Analysis ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
Flame Flashback

Flame flashback driven by Combustion Induced Vortex Breakdown (CIVB) represents one of the most severe reliability problems of modern gas turbines with swirl stabilized combustors. Former experimental investigations of this topic with a 500 kW burner delivered a model for the prediction of the CIVB occurrence for moderate to high mass flow rates. This model is based on a time scale comparison. The characteristic time scales were chosen following the idea that quenching at the flame tip is the dominating effect preventing upstream flame propagation in the center of the vortex flow. Additional numerical investigations showed that the relative position of the flame regarding the recirculation zone influences the interaction of flame and flow field. The recent analysis of turbulence and chemical reaction of data acquired with high speed measurement techniques applied during the CIVB driven flame propagation by the authors lead to the extension of the prediction model. As at the flame tip the corrugated flames regime prevails at low to moderate mass flow rates, a more precise prediction in this range of mass flow rates is achieved using a characteristic burnout time τb∼1/Sl for the reactive volume. The paper presents first this new idea, confirms it then with numerical as well as experimental data and extends finally the former model to a prediction tool that can be applied in the full mass flow range of swirl burners.

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