A comparative study of the performance of the mixed flow and radial flow variable geometry turbines for an automotive turbocharger

Ramesh, K; Prasad, B. V. S. S. S.; Sridhara, K

doi:10.1177/0954406218796043

Cited by 4 publications

(7 citation statements)

References 10 publications

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“…Even though that like-engine waveforms were well replicated through implemented solenoid-controlled valves at turbine and compressor boundaries, their study presented a major drawback that they used the air as a working fluid which can yield to an increasing uncertainty of the predicted turbocharger characteristics as it strongly depends on the thermodynamic properties of the working gas such as the specific calorific value. The same observation about the susceptible irrelevance of working gas was marked for the experimental work of Ramesh et al 18 where smallscale mixed and radial turbocharger turbines were studied. Their study revealed the advantage of higher efficiency of the mixed flow turbine more than 25% compared to the radial turbine.…”

Section: Introductionsupporting

confidence: 52%

Analysis of performance and time lag of turbocharger turbines fed with gasoline and diesel burnt gases and air under pulsating flow conditions

Ketata

Driss

2022

International Journal of Engine Research

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The turbine, an enabling component of turbochargers, is a seat of highly complex unsteady flow as well as varying gas compositions between diesel and gasoline engines. Thus, it is necessary to take into account different physical models when simulating such turbines. Researchers have often considered the turbine working gas as air, which may not lead to an accurate prediction of actual turbine characteristics. In the present work, the effect of the working gas on the performance of turbocharger turbines as well as on the turbo lag was investigated through a set of numerical simulations for six wastegate opening degrees from 0% up to 100% and under a wide range of the flow pulse frequency ranging from 33.33 up to 166.66 Hz. Four working fluids were involved in this study which are the gasoline burnt gas, diesel burnt gas, air with like gasoline engine waves, and air with like diesel engine waves. The performance of the turbine and its responsiveness quantified as the time lag with burnt gases from both diesel and gasoline engines were compared to those with air. Results showed totally deviated unsteady performance characteristics compared to the turbine working with air. Results also confirmed that considering the working fluid as air may not lead to a fair representation of the actual turbine performance characteristics. The findings of this work put emphasis on the importance of the gas composition when modeling such turbines by engineers especially during the design process where a good turbocharger-engine match has to be met.

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Section: Introductionsupporting

confidence: 52%

Analysis of performance and time lag of turbocharger turbines fed with gasoline and diesel burnt gases and air under pulsating flow conditions

Ketata

Driss

2022

International Journal of Engine Research

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“…The basic experimental test facility for steady state testing and its operating principle were discussed in detail by the authors in their previous paper, Ramesh et al. 6 Figure 5 shows the schematic of the cold air test rig with incorporating the features for conducting the transient response tests. For the transient tests, the quick-release on/off valve (QRV) is installed before the turbine inlet and its actuating system is marked within the dotted line.…”

Section: Experimental Test Set-up For Transient Response Testmentioning

confidence: 99%

“…The variation of turbine mass flow parameter (MFP) with turbine expansion ratio for different nozzle vanes opening can be referred from the authors’ previous work, figure 7 of Ramesh et al. 6…”

Section: Steady State Performancementioning

confidence: 99%

“…The values of turbine expansion ratio, in turn, are identified based on the turbine steady state experimental data, by referring to turbine mass flow parameter (MFP) against the expansion ratio results, as reported in figure 9 of Ramesh et al. 6…”

Section: Experimental Procedures For Transient Response Performancementioning

confidence: 99%

“…Ramesh et al. 6 compared the turbine performance for the radial flow and mixed flow VGT configurations for the similar turbine size, and demonstrated that at steady flow condition, the flow handling capacity of the VGT with mixed flow configuration is higher compared to VGT with radial flow configuration. In addition, for similar turbine mass flow parameter and pressure at inlet to the turbines, the combined turbine efficiency of the turbine with mixed flow variable geometry configuration is higher compared to the turbine with radial flow variable geometry configuration, importantly at lower turbine mass flow and turbine inlet pressure conditions (lower expansion ratio regions), which is more desirable operating conditions during engine transient operations.…”

Section: Introductionmentioning

confidence: 99%

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Transient performance of the mixed flow and radial flow variable geometry turbines for an automotive turbocharger

Kannan

Prasad

Sridhara³

2020

Proceedings of the Institution of Mechanical Engineers, Part C:

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In our previous paper, the steady-state test results of a mixed flow turbine with variable nozzle vanes for a turbocharger are reported. In this paper, the transient response of the same mixed flow turbine along with that of a similarly sized radial flow turbine is presented. The turbine size is suitable for handling the flow capacity of the diesel engines with swept volume up to 1.5 L. The previous experimental test set up is modified by adding a quick-release valve – actuation system before the turbine inlet to obtain a transient response. The radial and mixed flow turbines are tested for different turbine inlet pressures and for various opening positions of the nozzle vanes while matching the turbine mass flow parameters between radial and mixed flow turbines. Typically at nozzle vane openings corresponding to 50% mass flow parameter and 1.5 bar (abs) pressure at the inlet to the turbine, the transient response time for the turbine with mixed flow variable nozzle vanes configuration is about 0.770 s, as compared to 0.858 s for the turbine with radial flow variable nozzle vanes configuration.

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Turbocompound energy recovery option on a turbocharged diesel engine

Battista,

Bartolomeo,

Prospero

et al. 2023

J. Phys.: Conf. Ser.

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The transportation sector is living a transition era in which hybrid and electrified vehicles are replacing conventional vehicles, based on internal combustion engines. This is pushed by the recognized need for reducing fuel consumption and tailpipe emissions, considering primary pollutants and carbon dioxide as a greenhouse gas. In the transition path, hybridization and partial electrification of the powertrain play a crucial role. In this regard, the need for on-board electrical energy storage and utilization is increasing significantly and the possibility to recover wasted energy and convert it into electrical form is mandatory. This is especially true for commercial and heavy-duty vehicles, where full electrification is more difficult to be implemented. Waste Heat Recovery (WHR) has therefore become so important for vehicles, not only to directly reduce fuel consumption and related emissions but also to improve the feasibility of a generation of vehicles with a higher degree of hybridization that considers, for example, the electrification of auxiliaries following the so-called auxiliaries-on-demand management. Wasted heat refers mainly to exhaust heat from gases, where about one third of the fuel energy is disposed of. Among the various systems for WHR, engine turbo-compounding is approaching a mature technology. This technological option makes use of an additional turbine on the exhaust line of the engine, downstream of the turbocharging one, which converts the residual gas enthalpy into mechanical form. In this paper, the F1C Iveco 3.0 L turbocharged diesel engine is considered for verifying the performances of a turbo-compounding system. The engine was mounted on a dynamic engine test bench. In particular, the interactions with the original engine produced on the exhaust line were studied. Backpressure effects on the engine introduced by turbo-compounding were evaluated reversed in terms of extra fuel consumption. Moreover, the new equilibrium of the turbocharger was assessed and the related modifications to the engine were measured considering that the turbocharger has a control strategy based on the so-called Variable Geometry Turbine (VGT), via the modification of the Inlet Guide Vanes (IGV). The presence of a secondary turbine for WHR opens to a wider possibility of actuating the IGV and, so, the possibility to optimize the recovery considering the integrated system and all its degrees of freedom.

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A comparative study of the performance of the mixed flow and radial flow variable geometry turbines for an automotive turbocharger

Cited by 4 publications

References 10 publications

Analysis of performance and time lag of turbocharger turbines fed with gasoline and diesel burnt gases and air under pulsating flow conditions

Analysis of performance and time lag of turbocharger turbines fed with gasoline and diesel burnt gases and air under pulsating flow conditions

Transient performance of the mixed flow and radial flow variable geometry turbines for an automotive turbocharger

Turbocompound energy recovery option on a turbocharged diesel engine

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