Design and numerical simulation on coupled flow field of radial turbine with air-inlet volute

Abstract

As one of the core components of turbocharger or micro-turbine, radial turbine has the features of small size and high rotation speed. In order to explore the design method and flow mechanism of the turbine with a volute, a centimeter-scale radial turbine with a vaneless air-inlet volute was designed and simulated numerically to investigate the characteristics of the coupled flow field. The results show that the wheel efficiency of single passage computation without the volute is 80.1%. After accounting for the factors of the loss caused by the volute and the interaction between each passage, the performance is more accurate according to the whole flow passage computation with the volute. High load region gathers at the mid-span and the efficiency declines to 76.6%. The performance of the volute whose structure angle of the trapezoid section is equal to 70 degree is better. Unlike uniform inlet condition in single passage, more appropriate inlet flow for the impeller is provided by the rectification effect of the volute in full passage calculation. Flow parameters are distributed more evenly along the blade span and are generally consistent between each passage at the outlet of the turbine.

Keywords

radial turbine / aerodynamic design / whole flow passage / air-inlet volute

References

[1] Deng Q H, Niu J F, Mao J R, et al. Experimental and numerical investigation on overall performance of a radial inflow turbine for 100 kW microturbine[C], 2007.

[2] Roumeas M, Cros S. Aerodynamic investigation of a nozzle clearance effect on radial turbine performance[C], 2012.

[3] Jacobson S A. Aerothermal challenges in the design of a microfabricated gas turbine engine[C], 1998.

[4] Padzillah M H, Rajoo S, Martinez-Botas R F. Numerical assessment of unsteady flow effects on a nozzled turbocharger turbine[C], 2012.

[5] Carrillo R A, Nascimento M A, Velásquez E I, et al. Radial inflow turbine one and tri-dimensional design analysis of 600 kW simple cycle gas turbine engine[C], 2010.

[6] Cox G, Roberts A, Casey M. The development of a deviation model for radial and mixed-flow turbines for use in throughflow calculation[C], 2009.

[7] Epstein A H. Millimeter-scale, MEMS gas turbine engines[J]. Journal of Engineering for Gas Turbines and Power, 2004, 126(2): 205-226.

[8] Ebaid M S Y, Bhinder F S, Khdairi G H, et al. A unified approach for designing a radial flow gas turbine[J]. Journal of Turbomachinery, 2003, 125(3): 598-606.

[9] Kang S, Lee S J, Prinz F B. Size does matter: The pros and cons of miniaturization[J]. ABB Review, 2001, 2: 54-62.

[10] Tan C S, Hawthorne W R, McCune J E, et al. Theory of blade design for large deflections: Part II — Annular cascades[J]. Journal of Engineering for Gas Turbines and Power, 1984, 106(2): 354-365.

[11] Zangeneh M. Compressible three-dimensional design method for radial and mixed flow turbomachinery blades[J]. International Journal for Numerical Methods in Fluids, 1991, 13(5): 599-624.

[12] Peirs J, Reynaerts D, Verplaetsen F, et al. A microturbine for electric power generation[J]. Sensors and Actuators, A: Physical, 2004, 113(1): 86-93.

[13] Isomura K, Murayama M, Yamaguchi H, et al. Component development of micromachined gas turbine generators[C]. Technical Digest Power MEMS, 2002, 32-35.

[14] Isomura K, Murayama M. Development of microturbocharger and micro-combustor for a three-dimensional gas turbine at micro-scale[C], 2003.

[15] Isomura K, Murayama M, Teramoto S, et al. Experiment verification of the feasibility of a 100 W class micro-scale gas turbine at an impeller diameter of 10 mm[J]. Journal of Micromechanics and Microengineering, 2006, 16(9): 254-261.

[16] Shan X C, Zhang Q D, Sun Y F, et al. Design, fabrication and characterization of an air-driven microturbine device[J]. Journal of Physics: Conference Series, 2006, 34(1): 316-321.

[17] Glassman A J. Computer Program for Design and Analysis of Radial Inflow Turbines[R], 1976.

[18] Casey M, Robinson C. A new streamline curvature throughflow method for radial turbomachinery[C], 2008.

[19] Cumpsty N A. Compressor Aerodynamics[M], 2004, 2nd Edition New York: Krieger Scientific.