Next Article in Journal
Evaluation of Artificial Neural Network-Based Temperature Control for Optimum Operation of Building Envelopes
Previous Article in Journal
Macroalgae-Derived Biofuel: A Review of Methods of Energy Extraction from Seaweed Biomass
Previous Article in Special Issue
Modeling and Control of a Parallel Waste Heat Recovery System for Euro-VI Heavy-Duty Diesel Engines
Article Menu

Export Article

Open AccessArticle
Energies 2014, 7(11), 7223-7244;

Naturally-Forced Slug Flow Expander for Application in a Waste-Heat Recovery Cycle

Department of Mechanical and Manufacturing Engineering, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4, Canada
Author to whom correspondence should be addressed.
Received: 1 July 2014 / Revised: 20 October 2014 / Accepted: 21 October 2014 / Published: 10 November 2014
(This article belongs to the Special Issue Waste Heat Recovery—Strategy and Practice)
Full-Text   |   PDF [5448 KB, uploaded 17 March 2015]


This paper investigates a slug-flow expander (SFE) for conversion of high-pressure gas/vapor into kinetic energy of liquid slugs. The energy transfer from high-pressure to kinetic energy is quantified using thrust plate measurements. Non-dimensional thrust data is used to quantify performance by normalizing measured thrust by thrust for the same water flow rate at zero air flow rate. A total of 13 expander configurations are investigated and geometries with the shortest cavity length and the smallest exit diameter are found to result in the largest non-dimensional thrust increase. Results show that thrust augmentation increases with the initiation of slug flow in the SFE. The analysis performed on the normalized thrust readings suggested that as the water and air flow were increased to critical conditions, the liquid slugs produced by the SFE augmented the thrust measurements. The final performance evaluation was based on linear regression of the normalized thrust measurements where slug flow was generated for each SFE architecture. Greater magnitudes of the slope from the linear regression indicated the propensity of the SFE to augment thrust. This analysis confirmed that for the SFE configurations over the range of values investigated, the SFE increased thrust up to three times its original value at no air flow. Given the inherent multiphase nature of the slug-flow expander, application to systems involving expansion of wetting fluids (water as part of a waste-heat recovery system) or air with water droplet formation (as part of a compressed-air energy storage system) could be considered. View Full-Text
Keywords: waste-heat recovery; compressed air energy storage; expander waste-heat recovery; compressed air energy storage; expander
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

Share & Cite This Article

MDPI and ACS Style

de Witt, B.; Hugo, R. Naturally-Forced Slug Flow Expander for Application in a Waste-Heat Recovery Cycle. Energies 2014, 7, 7223-7244.

Show more citation formats Show less citations formats

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Energies EISSN 1996-1073 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top