Title: Exergetic optimisation of twin screw expanders

Authors: Hormoz Abolhasani; Mahdi Moghimi; Mahmoud Ebrahimi

Addresses: School of Mechanical Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran 16844, Iran ' School of Mechanical Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran 16844, Iran ' School of Mechanical Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran 16844, Iran

Abstract: Limited access to energy resources, air pollution and its subsequent detriments to ozone layer have accentuated the importance of green industry for recovering exergy from high-pressure flow to generate clean electrical power. Due to low maintenance costs, usage in two-phase fluids and longer lifespan, the twin screw expanders (TSEs) have attracted great attention though there is still much to be done to improve their performance. The complexity of computing in screw machines, as well as the time consuming of their simulation throughout the entire design space by the computational fluid dynamics (CFDs), requires the use of other complementary tools to optimise the performance of these types of machines. In this paper, based on laboratory model specification and experimental data, a TSE model was simulated and validated using CFD. Consequently, by helping design of experiments (DOE), a CFD alternative model is obtained called surrogate-based modelling (SBM) and the effect of three main geometric parameters on the expander's exergy efficiency were investigated in entire design space. Finally, a more efficient TSE with 86% exergy efficiency was obtained by using multi-objective genetic algorithm in the shortest time.

Keywords: exergy efficiency; surrogate-based modelling; SBM; twin screw expander; TSE; design of experiment; DOE.

DOI: 10.1504/IJEX.2019.104098

International Journal of Exergy, 2019 Vol.30 No.4, pp.360 - 375

Received: 22 Feb 2019
Accepted: 27 Jun 2019

Published online: 12 Dec 2019 *

Full-text access for editors Access for subscribers Purchase this article Comment on this article