Title: Effect of radial turbo-expander design on off-highway vehicle organic Rankine cycle system efficiency

Authors: Fuhaid Alshammari; Apostolos Karvountzis-Kontakiotis; Apostolos Pesyridis

Addresses: Centre of Advanced Powertrain and Fuels (CAPF), Department of Mechanical, Aerospace and Civil Engineering, Brunel University, Uxbridge UB8 3PH, London, UK ' Centre of Advanced Powertrain and Fuels (CAPF), Department of Mechanical, Aerospace and Civil Engineering, Brunel University, Uxbridge UB8 3PH, London, UK ' Centre of Advanced Powertrain and Fuels (CAPF), Department of Mechanical, Aerospace and Civil Engineering, Brunel University, Uxbridge UB8 3PH, London, UK

Abstract: Compared to other waste heat recovery (WHR) technologies, organic Rankine cycle (ORC) system is regarded as the most candidate technology due to its simplicity, low cost and small back pressure impact. Expanders are crucial components of an ORC system along with working fluid. In this simulation study, an in-house code has been developed to explore the effect of various working fluids on optimum radial expander geometry. In addition, an off-design turbine analysis has been employed in order to evaluate the performance of the calculated expander geometry under various engine operating conditions. Finally, the effect of various expanders' designs on fuel consumption and emissions of an off-highway vehicle is presented. Compared to conventional diesel powertrain systems, the WHR system showed an up to 5.7% increase in brake torque and brake power and a 5.4% reduction in BSFC. The results also showed that working fluid and expander speed are critical parameters on the performance of the proposed powertrain configuration.

Keywords: diesel engines; organic Rankine cycle; ORC; radial turbine design; waste heat recovery; WHR.

DOI: 10.1504/IJPT.2018.090364

International Journal of Powertrains, 2018 Vol.7 No.1/2/3, pp.72 - 93

Received: 15 Jan 2017
Accepted: 24 Jul 2017
Published online: 13 Mar 2018 *

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