Analytical investigation of simultaneous effects of friction and heating to a supersonic nucleating Laval nozzle

Authors

1 Ferdowsi University of Mashhad, Mashhad, Iran

2 Hakim Sabzevari University,Sabzevar, Iran‎

Abstract

In supersonic water vapor flows of low pressure turbines, the nucleation phenomena and consequent condensation is commonly observed. Internal heat transfer which is caused by phase change is strongly irreversible and has unwanted effects on turbine efficiency. Also, the strike of formed droplets on the surfaces results in large amounts of mechanical damages. Condensation heat release to supersonic flow is named condensation shock and leads to a considerable pressure rise which in turn reduces the outlet velocity and occasionally causes severe oscillations and makes the flow supercritical. The authors have presented a novel analytical approach for the reduction of these unwanted results in Laval nozzles by volumetric heating of the convergent section. In this paper and in continuation of the series of papers by the authors, one dimensional, supersonic and two-phase flow is modeled analytically and the simultaneous effects of volumetric heat transfer and friction in the convergent nozzle are investigated. It is concluded that the simultaneous use of friction and volumetric heatingcan be an appropriate and useful technique for the control of two-phase flow conditions and keeping them in the desired range.

Keywords

Scientia Iranica
Volume 21, Issue 5
Transactions on Mechanical Engineering (B)
October 2014
Pages 1700-1708

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