Effect of Turbulent Prandtl Number on the Performance of Supercritical Carbon Dioxide Turbulent Flow in a Vertical Round Tube With High Heat Flux
Supercritical carbon dioxide(S-CO2)is widely used in coal-fired thermal power generation,concentrated solar power generation and nuclear reactors because of its low corrosiveness,low critical parameters and high efficiency.In these conditions,S-CO2 is usually turbulent flow with high temperature,high pressure and high heat flux.At present,the turbulence model is mainly used for subcritical and near-critical flow problems,whereas it is not suitable for supercritical fluid flow.Therefore,a study is carried out on the characteristics of S-CO2 turbulent flow in a vertical tube under supercritical conditions far from the pseudo-critical point.A multi-fields coupled numerical model of S-CO2 in a round tube with uniform heating is developed and validated by our experimental data.The effect of the turbulent Prandtl number(Prt)on the turbulence model is investigated,and the effect of key operating parameters is also discussed.The results show that Prt has an important effect on the heat transfer of the S-CO2 turbulent flow with high heat flux.For the SST turbulence model,when Prt is reduced from 1 to 0.65～0.70,the mean relative error(MRE)of the inner wall temperature can be reduced by approximately 3.16%and the convective heat transfer coefficient can be increased by 25.21%.The modification of Prt can effectively improve the accuracy of SST turbulence modeld.This paper also provides a theoretical basis for the development of S-CO2 cycle under high heat flux.
国家科技期刊平台
NSTL
万方数据
