Loss analysis of a mix-flow turbine with nozzled twin-entry volute at different admissions

Xue, Yingxian; Yang, Mingyang; Martinez-Botas, Ricardo; Romagnoli, Alessandro; Deng, Kangyao

doi:10.1016/j.energy.2018.10.075

Cited by 30 publications

(24 citation statements)

References 11 publications

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“…It means a higher work in the centrifugal forces field than the Shroud branch with a lower radius ratio. Figure 18 also shows slightly higher peak efficiency at Hub branch, probably due to the higher trimming (higher specific work) and the lower tip leakage losses when the flow is concentrated in hub branch than in shroud [44,45]. For predicting the same turbine outlet temperature as in experiments at different flow admission conditions, a look-up table is generated with the extrapolated efficiency, blade to jet speed ratio, and reduced turbine speeds of MFR 0 and 1 separately, corresponding to hub and shroud entries in the turbine T#1TE.…”

Section: Mfr X B T E C T E F T Ementioning

confidence: 98%

A Robust Adiabatic Model for a Quasi-Steady Prediction of Far-Off Non-Measured Performance in Vaneless Twin-Entry or Dual-Volute Radial Turbines

Serrano¹,

Arnau²,

García-Cuevas³

et al. 2020

Applied Sciences

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The current investigation describes in detail a mass flow oriented model for extrapolation of reduced mass flow and adiabatic efficiency of double entry radial inflow turbines under any unequal and partial flow admission conditions. The model is based on a novel approach, which proposes assimilating double entry turbines to two variable geometry turbines (VGTs) using the mass flow ratio ( MFR ) between the two entries as the discriminating parameter. With such an innovative approach, the model can extrapolate performance parameters to non-measured MFR s, blade-to-jet speed ratios, and reduced speeds. Therefore, the model can be used in a quasi-steady method for predicting double entry turbines performance instantaneously. The model was validated against a dataset from two different double entry turbine types: a twin-entry symmetrical turbine and a dual-volute asymmetrical turbine. Both were tested under steady flow conditions. The proposed model showed accurate results and a coherent set of fitting parameters with physical meaning, as discussed in this paper. The obtained parameters showed very similar figures for the aforementioned turbine types, which allows concluding that they are an adequate set of values for initializing the fitting procedure of any type of double entry radial turbine.

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Section: Mfr X B T E C T E F T Ementioning

confidence: 98%

A Robust Adiabatic Model for a Quasi-Steady Prediction of Far-Off Non-Measured Performance in Vaneless Twin-Entry or Dual-Volute Radial Turbines

Serrano¹,

Arnau²,

García-Cuevas³

et al. 2020

Applied Sciences

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“…Importantly, the loss in the nozzle is the most strongly influenced by the inlet conditions, followed by the rotor and the volute. Specifically, the peak loss happens at 'A' and 'B' which correspond to the two partial with the phenomenon observed in steady conditions [25]. The highest loss and hence lowest efficiency tends to happen at partial admission conditions because of strong mixing loss and highly distorted flow in spanwise direction at inlet of the rotor.…”

Section: Turbine Performancementioning

confidence: 69%

Unsteady performance of a mixed-flow turbine with nozzled twin-entry volute confronted by pulsating incoming flow

Xue

Yang

Martinez-Botas

et al. 2019

Aerospace Science and Technology

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Turbine with twin-entry volute has advantage of utilizing energy from pulsatile exhaust gas and improving low-speed torque of an internal combustion engine. This paper investigates unsteady performance of a mixed flow turbine with nozzled twin-entry volute confronted by pulsatile incoming flow. The turbine performance at pulsating conditions with different Strouhal numbers (St) is studied via experimentally validated numerical method. Results show that the unsteadiness of turbine performance is enhanced as Strouhal number increases. In particular, the cycle-average efficiency at St=0.522 is about 3.4% higher than that of quasi-steady condition (St=0). Instantaneous loss breakdown of the turbine shows that the entropy generation rate of turbine components reduces evidently at pulsating conditions as Strouhal number increases, especially for the nozzle. Specifically, the cycle-averaged reduction of the loss in the nozzle is 37.3% at St=0.522 compared with that of St=0. The flow analysis shows that secondary flow which contributes to the majority of loss in the nozzle, including flow separation, horseshoe vortex, and reversed flow near the leading edge, are notably alleviated as Strouhal number increases. The alleviation of the flow structures are resulted from two reasons: one is that the flow distortion at the nozzle inlet is evidently depressed by the pulsating conditions, 2 the other is that the inertia of the low momentum flow in the nozzle damps flow evolution at pulsating incoming flow. Consequently, the loss is reduced and the turbine performance is benefited by the pulsating inflows.

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“…The results showed that the power, heat transfer and irreversible effect of the downstream components of the turbine were not significantly affected by upstream structures. Yang et al [13,14] investigated the impact of a pulsating flow on the unsteady performance of a radial turbine with a twin channel volute. This study established the basic principles gaverning the 'unsteadiness' of turbine performance under pulsating conditions.…”

Section: Introductionmentioning

confidence: 99%

The influence of a radial turbine volute on back-disk impingement cooling performance

Lü

Wenjiao³

2020

J Braz. Soc. Mech. Sci. Eng.

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Due to the restricted size of micro-gas turbines, the difficulty of cooling their radial turbines and raising their inlet temperature has been an ongoing focus in their research. In this paper, a back-disk impingement cooling technology for radial turbines is proposed. The study focuses on the influence of the non-uniform circumferential flow field generated by radial turbine volutes on the back-disk's cooling characteristics. The study was carried out by using a conjugated heat transfer numerical simulation method. The results showed that the circumferential non-uniform distribution of the flow field caused by the volute can significantly impact the relative distribution of cooling efficiency across the surface of the back-disk and can decrease the average cooling efficiency of the back-disk surface by 1.8-6.0% in comparison with when the flow field is uniform. Back-disk jet cooling reduces the efficiency of a turbine and, if the volute is generating a non-uniform flow field, this further decreases the turbine's efficiency. It was found, however, that the influence of back-disk jet cooling on the expansion ratio of the turbine can be ignored.

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Loss analysis of a mix-flow turbine with nozzled twin-entry volute at different admissions

Cited by 30 publications

References 11 publications

A Robust Adiabatic Model for a Quasi-Steady Prediction of Far-Off Non-Measured Performance in Vaneless Twin-Entry or Dual-Volute Radial Turbines

A Robust Adiabatic Model for a Quasi-Steady Prediction of Far-Off Non-Measured Performance in Vaneless Twin-Entry or Dual-Volute Radial Turbines

Unsteady performance of a mixed-flow turbine with nozzled twin-entry volute confronted by pulsating incoming flow

The influence of a radial turbine volute on back-disk impingement cooling performance

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