Effect of inter-stage phenomena on the performance prediction of two-stage turbocharging systems

Avola, Calogero; Copeland, Colin; Burke, Richard; Brace, Chris

doi:10.1016/j.energy.2017.06.067

Cited by 17 publications

(4 citation statements)

References 22 publications

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“…Galindo et al 29 investigated the performance of the two-stage turbocharging approach, and the results presented that the overall performance of the 2ST system for the entire operative range and characterized the optimum control of the components for various operating conditions. Avola et al 30 investigated the accuracy of performance measurement in two-stage turbocharging systems in the context of aerothermal interstage phenomena and concluded that the turbine net efficiency was reduced by about 10% at elevated corrected mass flow operations. The 2ST is also adopted at high altitudes or in flight, as it can offer a high compression pressure ratio.…”

Section: Introductionmentioning

confidence: 99%

Turbocharging strategy among variable geometry turbine, two-stage turbine, and asymmetric two-scroll turbine for energy and emission in diesel engines

Zhu

Sun

Zheng

2019

Proceedings of the Institution of Mechanical Engineers, Part A:

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Energy saving and emission reduction are very urgent for internal combustion engines. Turbocharging and exhaust gas recirculation technologies are very significant for emissions and fuel economy of internal combustion engines. Various after-treatment technologies in internal combustion engines have different requirements for exhaust gas recirculation rates. However, it is not clear how to choose turbocharging technologies for different exhaust gas recirculation requirements. This work has indicated the direction to the turbocharging strategy among the variable geometry, two-stage, and asymmetric twin-scroll turbocharging for different exhaust gas recirculation rates. In the paper, a test bench engine experiment was presented to validate the numerical models of the three diesel engines employed with the asymmetric twin-scroll turbine, two-stage turbine, and variable geometry turbine. On the basis of the numerical models, the turbocharging routes among the three turbocharging approaches under different requirements for EGR rates are studied, and the other significant performances of the three turbines were also discussed. The results show that there is an inflection point in the relative advantages of asymmetric, variable geometry, and two-stage turbocharged engines. At the full engine load, when the EGR rate is lower than 29%, the two-stage turbocharging technology has the best performances. However, when the exhaust gas recirculation rate is higher than 29%, the asymmetric twin-scroll turbocharging is the best choice and more appropriate for driving high exhaust gas recirculation rates. The work may offer guidelines to choose the most suitable turbocharging technology for engine engineers and manufacturers to achieve further improvements in engine energy and emissions.

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Section: Introductionmentioning

confidence: 99%

Turbocharging strategy among variable geometry turbine, two-stage turbine, and asymmetric two-scroll turbine for energy and emission in diesel engines

Zhu

Sun

Zheng

2019

Proceedings of the Institution of Mechanical Engineers, Part A:

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“…Today, the receipt of new data on the features of gas-dynamics and heat transfer in gas-air tracts of turbocharged engines is an important task, since the efficiency of power machines based on ICEs depends on the perfection of these processes [1][2][3]. Modern research in this field is devoted to the study of the parameters of gas flows at the inlet and outlet of the TC turbine [4][5][6], heat transfer inside the compressor [7], the thermal effect of the turbine on the compressor in the composition of the TC [8] and ways to improve the efficiency of the turbocharger [9,10].…”

Section: Introductionmentioning

confidence: 99%

Nonstationary gas-dynamics and local heat transfer in the output channel of the turbocharger compressor

2019

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Thermomechanical characteristics of the gas flow at the turbocharger compressor outlet largely determine the quality of the intake process in piston engines with boost. The article presents the results of an experimental study of gas-dynamics and heat transfer of gas flows after compression in a turbocharger centrifugal compressor. A brief description of the experimental setup, the configuration of pipes under investigation, the measuring system and the experimental features are given. The studies were carried out on a free compressor, i.e. without considering the piston part. Different conditions in the compressor outlet channel were created by installing special nozzles with different hydraulic resistances. It has been established that the local heat transfer increases from 23 to 46 % with an increase in the turbocharger rotor speed, depending on the outlet channel configuration. It should be noted that an increase in rotor speed is also accompanied by an increase in air flow through the channel. The increase in flow rate was from 10 to 42 %.

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“…The compressor was isolated from the engine inlet to work against a compressor back pressure valve (CBPV). The setup was used to observe certain unsteady flow TC behaviors [24] [25], and used to improve 1D modeling accuracies [26] [27] and identify the effect of modifying the positions of intercooler on a 2 stage boosting system [28]. Although similar engine gas stand (EGS) rigs are in operation globally, there are a few important features to note here that allows the study of complex air handling systems.…”

Section: Introductionmentioning

confidence: 99%

“…Although similar engine gas stand (EGS) rigs are in operation globally, there are a few important features to note here that allows the study of complex air handling systems. The facility discussed in this paper is the next generation of the facility discussed in reference [24] to [28] which had difficulties measuring turbine-side flow.…”

Section: Introductionmentioning

confidence: 99%

Design of an Advanced Air Path Test Stand for Steady and Transient Evaluation

Vijayakumar

Burke

Liu

et al. 2018

Volume 2: Emissions Control Systems; Instrumentation, Controls, and Hybrids; Numerical Simulation; Engine Design and Mechanical

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Different air systems such as turbochargers (TC), hybrid boosting, turbo compounding and exhaust gas recirculation (EGR) are increasingly used to improve the thermal efficiency of internal combustion engines (ICE). One dimensional (1D) gas dynamic codes supports their development and integration by modelling the engine and air systems and reducing testing time. However, this approach currently relies on steady flow characteristic maps which are inaccurate for simulating transient engine conditions. This is a key weakness of using gas-stand measured maps in engine simulations. Performing TC mapping on an engine would in principle solve this problem, however engine-based mapping is limited by the engine operating range and on these facilities, high-precision measurements are challenging. In addition, simple turbocharging can no longer be constrained to an individual TC supplying boost air to an engine. Instead, modern downsized engines require air-path system making use of multiple components including TCs, mechanical superchargers, electrically driven compressors (EDCs), EGR paths and control valves. Thus studying multiple air systems requires an experimental test facility to understand how they work in synergy. This is also useful in developing empirical models to minimize test time. Therefore the aim of this paper is to present a novel experimental facility that is flexibly designed for evaluating air systems individually and also at the system level representing a complicated air path both in steady and transient condition. The advanced test facility is built around a 2.2 l diesel engine to test the above air systems which can isolate the thermal and load transients from engine pulsating flows. Removing the flow pulsation allows study of the system characteristics in a steady state. Several examples of component and system level tests including a two-stage air path comprising of a VGT (variable geometry turbine) TC and a 48V EDC with typical operating condition (provided by 1D modeling) are discussed.

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Effect of inter-stage phenomena on the performance prediction of two-stage turbocharging systems

Cited by 17 publications

References 22 publications

Turbocharging strategy among variable geometry turbine, two-stage turbine, and asymmetric two-scroll turbine for energy and emission in diesel engines

Turbocharging strategy among variable geometry turbine, two-stage turbine, and asymmetric two-scroll turbine for energy and emission in diesel engines

Nonstationary gas-dynamics and local heat transfer in the output channel of the turbocharger compressor

Design of an Advanced Air Path Test Stand for Steady and Transient Evaluation

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