Mapping scroll expander performance for organic working fluids using dimensionless parameters in N-s-D-s diagram

Narasimhan, Arun Kumar and Wickramaratne, Chatura and Kamal, Rajeev and Goswami, D. Yogi and Singh, Punit (2019) Mapping scroll expander performance for organic working fluids using dimensionless parameters in N-s-D-s diagram. In: ENERGY, 182 . pp. 739-752.

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Abstract

This paper presents an analysis of single-stage scroll expander performance for pure fluids and their zeotropic mixtures in supercritical conditions using dimensionless parameters, namely specific speed (N-s) and specific diameter (D-s). Scroll geometries with different aspect ratios were modeled for a range of expander inlet temperatures. The expander efficiency was modeled accounting for losses due to leakage, friction, and over- and under-expansion. The expander efficiency was plotted as a function of two dimensionless parameters to analyze the applicability domain of scroll expanders. For a particular expander inlet temperature (T-in), zeotropic mixtures result in more compact scroll geometries than pure fluids, leading to reduced losses and better expander efficiency. Any increase in T-in results in larger scrolls leading to higher leakage and thereby lower efficiency. At suitable operating conditions, an optimized scroll expander design can achieve expansion efficiency as high as 75%. Sub-optimal scroll designs for a given application lead to lower expansion efficiency due to over- or under-expansion losses.

Item Type:	Journal Article
Publication:	ENERGY
Publisher:	PERGAMON-ELSEVIER SCIENCE LTD
Additional Information:	copyright for this article belongs to PERGAMON-ELSEVIER SCIENCE LTD
Keywords:	Scroll expander; Dimensionless diagram; Performance mapping; Volume ratio; Expander efficiency
Department/Centre:	Division of Interdisciplinary Sciences > Interdisciplinary Centre for Energy Research Division of Mechanical Sciences > Centre for Sustainable Technologies (formerly ASTRA)
Date Deposited:	09 Sep 2019 10:10
Last Modified:	09 Sep 2019 10:10
URI:	http://eprints.iisc.ac.in/id/eprint/63477

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