The influence of secondary flow structures in a turbocharger turbine housing in steady state and pulsating flow conditions

Lee, Samuel P.; Jupp, Martyn; Nickson, A.K.

doi:10.1109/icmae.2016.7549526

Cited by 8 publications

(7 citation statements)

References 14 publications

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“…This behavior is the result of the development of flows within the volute and was discussed previously by Lee et al 9 Figure 24 shows contours of radial velocity and surface streamlines on six planes around the volute at 40 Hz pulse frequency at both the minimum and maximum incidence running points. The positions of the six planes are 54 , 72 , 90 , 126 , 198 and 270 .…”

Section: Operating Conditionssupporting

confidence: 64%

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Analysis of leading edge flow characteristics in a mixed flow turbine under pulsating flows

Lee

Jupp

Barrans

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part A:

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Current trends in the automotive industry towards engine downsizing means turbocharging now plays a vital role in engine performance. A turbocharger increases charge air density using a turbine to extract waste energy from the exhaust gas to drive a compressor. Most turbocharger applications employ a radial inflow turbine. However, to ensure radial stacking of the blade fibers and avoid excessive blade stresses, the inlet blade angle must remain at zero degrees, creating large incidence angles. Alternately, mixed flow turbines can offer non-zero blade angles while maintaining radial stacking of the blade fibers and reducing leading edge separation at low velocity ratios. Furthermore, the physical blade cone angle introduced reduces the blade mass at the rotor outer diameter reducing rotor inertia and improving turbine transient response. The current paper investigates the performance of a mixed flow turbine under a range of pulsating inlet flow conditions. A significant variation in incidence across the LE span was observed within the pulse, where the distribution of incidence over the LE span was also found to change over the duration of the pulse. Analysis of the secondary flow structures developing within the volute shows the non-uniform flow distribution at the volute outlet is the result of the Dean effect in the housing passage. In-depth analysis of the mixed flow effect is also included, showing that poor axial flow turning ahead of the rotor was evident, particularly at the hub, resulting in modest blade angles. This work shows that the complex secondary flow structures that develop in the turbine volute are heavily influenced by the inlet pulsating flow. In turn, this significantly impacts the rotor inlet conditions and rotor losses.

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Section: Operating Conditionssupporting

confidence: 64%

“…The development of volute secondary flows in a circular cross sectioned volute was investigated by Lee et al 9 under both steady state and pulsating flow conditions. The authors found Dean-like vortex development in the volute and a significant variation in volute outflow conditions as a result.…”

Section: Introductionmentioning

confidence: 99%

Analysis of leading edge flow characteristics in a mixed flow turbine under pulsating flows

Lee

Jupp

Barrans

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part A:

View full text Add to dashboard Cite

show abstract

“…The development of volute secondary flows in a circular cross sectioned volute was investigated by Lee et al [13] under both steady state and pulsating flow conditions for a radial turbine. The authors found Dean-like vortex development in the volute and a significant variation in volute outflow conditions as a result.…”

Section: Introductionmentioning

confidence: 99%

The Impact of Volute Aspect Ratio on the Performance of a Mixed Flow Turbine

et al. 2017

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Current trends in the automotive industry towards engine downsizing mean turbocharging now plays a vital role in engine performance. A turbocharger increases charge air density using a turbine to extract waste energy from the exhaust gas to drive a compressor. Most turbocharger applications employ a radial inflow turbine. However, mixed flow turbines can offer non-zero blade angles, reducing leading edge (LE) separation at low velocity ratios. The current paper investigates the performance of a mixed flow turbine with three different volute aspect ratio (AR) designs (AR = 0.5, 1 and 2). With constant A/r (ratio of volute area to centroid radius), the AR = 0.5 volute design produced a 4.3% increase in cycle averaged mass flow parameter (MFP) compared to the AR = 2 design. For the purpose of performance comparison, it was necessary to manipulate the volute A/r's to ensure constant MFP for aerodynamic similarity. With the volute A/r's manipulated to ensure constant MFP for aerodynamic similarity, the maximum variation of cycle averaged normalized efficiency measured between the designs was 1.47%. Purely in the rotor region, the variation in normalized cycle averaged efficiency was 1%. The smallest tested volute aspect ratio showed a significant increase in volute loss while the ARs of 1 and 2 showed similar levels of loss. The smallest AR volute showed significant secondary flow development in the volute. The resulting variation in LE incidence was found to vary as a result.

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“…They will entangle each other and a new swirling flow will emerge downstream of the junction. This new swirling flow plays a decisive role in the performance of LPT [13]. The swirling flow is deeply influenced by the bypass flow in such a case, thus the bypass flows with different injected locations are expected to diversely influence the turbine performance.…”

Section: Introductionmentioning

confidence: 99%

Investigation of inter-stage passive flow control for turbine performance improvement on regulated two-stage turbocharger

Zou

Yang

Zhou

et al. 2022

J. Phys.: Conf. Ser.

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The flow field coupling effect between the HPT (high pressure turbine) and LPT (low pressure turbine) introduces a particular flow structure to the two-stage turbocharging system. Compared to the isolated turbines, the performance of these two connected turbines will inevitably be affected by each other. However, in the open state of the bypass valve, the influence of the bypass flow on this flow field coupling effect is still unknown. In this study, the inter-stage performance interaction of regulated two-stage turbocharger was investigated through the three-dimensional numerical method. With the bypass valve open, the influence of different positions of the bypass branch on the inter-stage coupling effects is investigated. The results manifest that the different positions of the bypass branch significantly change the performance of low pressure turbine and the flow interactions within the inter-stage. When the bypass branch is on the right, the LPT efficiency improves by approximately 2.2%. The detailed flow field analysis of the inter-stage pipe, volute and rotor is conducted to reveal the flow mechanism behind the inter-stage interactions. Based on this investigation, a new passive flow control scheme is proposed to ameliorate the swirling flow at the LPT inlet and improve the performance of LPT.

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The influence of secondary flow structures in a turbocharger turbine housing in steady state and pulsating flow conditions

Cited by 8 publications

References 14 publications

Analysis of leading edge flow characteristics in a mixed flow turbine under pulsating flows

Analysis of leading edge flow characteristics in a mixed flow turbine under pulsating flows

The Impact of Volute Aspect Ratio on the Performance of a Mixed Flow Turbine

Investigation of inter-stage passive flow control for turbine performance improvement on regulated two-stage turbocharger

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