Revisiting the Rayleigh-Taylor instability and critical heat flux with R-123 for different heater sizes and pressures

Abstract

This paper presents how the relationships between the Rayleigh-Taylor (RT) instability and the critical heat flux (CHF) and minimum heat flux (MHF) change under different experimental conditions. Experimental observations of the RT instability wavelength for various wire surface diameters and system pressures were analyzed to characterize the CHF and MI-IF in a pressurized wire pool boiling facility. Three types of heater diameter surfaces were considered: 03, 0.5, and 0.7 mm diameter bare Ni Cr wires. The experimental system pressure ranged from 1 bar to 9 bar for observation of the RT instability wavelength changes in the CHF and MHF with the 0.5 mm diameter wire. High-speed video was used to analyze the changes in the RT instability wavelength under each experimental condition. The wavelengths at the CHF and MHF regions were characterized according to the heater diameter and system pressure. The results showed that using the change in the RT instability wavelength is a viable means of determining the variations in the CHF and MHF during pool boiling.