Modelling of non-stationary pressure fluctuations during boiling in a minichannel

Department of Mechanics and Applied Computer Science, Faculty of Mechanical Engineering, Bialystok University of Technology, Wiejska 45 C, 15-351, Bialystok, Poland

^* Corresponding author: r.mosdorf@pb.edu.pl

Abstract

Boiling in a minichannel occurring at a low mass flow rate is accompanied by non-stationary twophase flow. The analysis of pressure fluctuations during non-stationary boiling in minichannel shows that quasi-periodic changes in flow patterns can be observed in such fluctuations. We can define in such a way the sequences, which are called “oscillating boiling patterns”. In the present paper the model, which allows us to simulate the appearance of “oscillating boiling patterns” has been presented. In the proposed model the mass flow rate changes (because of evaporation and condensation) are modelled by compressible volumes representing various sizes bubbles. In the paper the good quality agreement between experimental data and simulation results has been achieved. Experimental data was collected during the boiling in open minichannels system with inner diameter of 1 mm.