Sage Journals: Discover world-class research

Abstract

The high boost pressures and fuel–air ratios required for the next generation of turbocharged diesel engines imply an increased turbine expansion ratio without an increase in the speed of rotation. This leads to a requirement for high peak efficiency at lower values of blade speed/isentropic expansion velocity U/C than are normal today. The objective of this project was to achieve this with a mixed flow rotor with a positive inlet blade angle. Two rotors were manufactured and tested: one a ‘constant blade angle’ design and the other a ‘constant incidence’ design. In practice both achieved a peak efficiency at a low U/C value, but the constant blade angle design, at 0.84 total to static efficiency, was significantly more efficient than the constant incidence design at 0.77. These efficiencies are highly competitive, compared to current radial turbine design. It is suggested that the reasons for this difference are a lack of understanding of the incidence and its effects on a mixed flow rotor, and a region of diffusion in the shroud-trailing edge corner of the suction surface, apparently worse for the constant incidence design.

Get full access to this article

View all access options for this article.

References

Dale

Watson

Vaneless radial turbocharger turbine performance. Conference on Turbocharging and turbochargers, 1986, pp. 65–76 (Mechanical Engineering Publications, London).

Yeo

J. H.

Baines

N. C.

Pulsating flow behaviour in a twin-entry vaneless radial inflow turbine. IMechE Conference on Turbocharging and turbochargers, 1990, pp. 113–122 (Mechanical Engineering Publications, London).

Chen

Steady and unsteady performance of vaneless radial inflow turbines. PhD thesis, University of Manchester, Institute of Science and Technology, 1990.

Baines

N. C.

Wallace

F. J.

Whitfield

Computer-aided design of mixed flow turbines for turbochargers. Trans. ASME, J. Engng for Power, 1978, 101, 440–449.

Yamaguchi

Nishiyama

Horlai

Kasuya

High performance Komatsu KTR150 turbocharger. SAE paper 840019, 1984.

Naguib

Experience with the modern RR151 turbocharger for high-speed diesel engines. IMechE Conference on Turbocharging and turbochargers, 1986, pp. 105–112 (Mechanical Engineering Publications, London).

Cheng

C. C.

Gibbs

C. A.

The design and testing of a mixed flow turbine for turbochargers. SAE paper 890644, 1989.

Rodgers

High pressure ratio radial turbine design constraints. VKI lecture series 1987–07, 1987.

Rohlik

H. E.

Analytical determination of radial inflow turbine design geometry for maximum efficiency. NASA TN D–4384, 1968.

10.

Wallace

F. J.

Baines

N. C.

Whitfield

A unified approach to the one-dimensional analysis and design of radial and mixed flow turbines. ASME paper 76–GT–100, 1976.

11.

Rodgers

Mainline performance prediction for radial inflow turbines. VKI lecture series 1987–07, 1987.

12.

Abidat

Design and testing of a highly loaded mixed flow turbine. PhD thesis, Imperial College, University of London, 1991.

13.

Forrest

A. R.

Interactive interpolation and approximation by Bezier polynomials. Computer J., 1972, 15, 71–79.

14.

Casey

M. V.

A computational geometry for the blades and internal flow channels of centrifugal compressors. Trans. ASME, J. Engngfor Power, 1983, 105, 288–295.

15.

Katsanis

Use of arbitrary quasi-orthogonals for calculating flow distribution in the meridional plane. NASA TN D–2546, 1964.

16.

Katsanis

Use of arbitrary quasi-orthogonals for calculating flow distribution on a blade-to-blade surface in a turbomachine. NASA TN D–2809, 1965.

17.

Pullen

K. R.

Design and development of a small gas turbine and high speed generator. PhD thesis, Imperial College, University of London, 1991.

18.

Baines

N. C.

Yeo

J. H.

Flow in a radial turbine under equal and partial admission conditions. IMechE Conference on Turbo-machinery, 1991, pp. 103–112 (Mechanical Engineering Publications, London).

Design of a Highly Loaded Mixed Flow Turbine

Abstract

Get full access to this article

References