New Friction Factor Correlation for Phase-Change Flow in Plate Heat Exchangers

Abstract

This article reports a new two-phase friction factor correlation for condensing and evaporating flows in plate heat exchangers. Over a thousand condensation pressure drop data compiled from seventeen articles were reduced to a two-phase friction factor correlation and successfully evaluated with data not used for correlation development. Similarly, over two thousand evaporation pressure drop data were collected from twenty-four articles and were empirically modeled to yield a two-phase friction factor, which was also successfully validated with independent data. The condensation friction factor correlation fit 72% of the data within ±50% and modeled 92% of the evaluation data within ±50%. Similarly, the evaporation friction factor correlation fit 64.9% of the data within ±50 and 89.8% of the evaluation data within ±50%. Pressure drop in condensers was predominantly due to convective condensation and buoyancy forces. Inertial forces and convective boiling were mainly responsible for the pressure drop in evaporators. As the Weber number was much <1, drop condensation and nucleate boiling were insignificant. Meta-analysis strongly recommended deploying plate heat exchangers as condensers for lowering the pressure drop and was inconclusive for evaporators.

Acknowledgments

The authors thank the University of Pretoria and the Vellore Institute of Technology for the research resources.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Yagnavalkya Mukkamala

Yagnavalkya Mukkamala is a Professor of Mechanical Engineering at Vellore Institute of Technology, India. He received his Ph.D. in Mechanical Engineering from the same university in 2008 and his M.S. in Mechanical Engineering from Virginia Polytechnic Institute and State University (USA) in 1993. He has published seventeen articles in various peer-reviewed journals and peer-reviewed conference articles. He has completed several funded projects as a principal investigator for the Government of India and numerous as a student investigator for the US Department of Energy and NASA. He has been cited over two hundred and ten times and has an h-index of over eight. His research interests include enhanced heat transfer, design of enhanced heat exchangers, and automotive aerodynamics.

Jaco Dirker

Jaco Dirker is an Associate Professor in Mechanical Engineering at the University of Pretoria, South Africa. He received his Ph.D. from Rand Afrikaans University (University of Johannesburg) in 2004. He has published 44 peer-reviewed journals and 44 peer-reviewed conference articles. He has completed five research projects, with the most recent project being funded by the Royal Society of the United Kingdom for over R 9 million (South African Rand). He is a clean energy and enhanced heat transfer specialist and has supervised several doctoral theses and post-doctoral scholars. He is a registered professional engineer at the Engineering Council of South Africa.