Heat Transfer and Hydraulic Resistance in Turbulent Flow in Vertical Round Tubes at Supercritical Pressures-Part 1: Results From Numerical Simulations Using Algebraic Turbulent Viscosity Models

摘要

The review of numerical studies on supercritical pressure (SCP) coolants heat transfer and hydraulic resistance in turbulent flow in vertical round tubes based on Reynolds-averaged Navier-Stokes (RANS) equations and different models for turbulent viscosity is presented. The paper is the first part of the general analysis, the works based on using algebraic turbulence models of different complexity are considered in it. The main attention is paid to Petukhov-Medvetskaya and Popov et al. models. They were developed especially for simulating heat transfer in tubes of the coolants with significantly variable properties (droplet liquids, gases, and SCP fluids) under heating and cooling conditions. These predictions were verified on the entire reliable experimental database known at that time (the data for SCP H2O, CO2, N-2, He, etc.). It is shown that in the case of turbulent flow in vertical round tubes, these models make it possible predicting heat transfer and hydraulic resistance characteristics of SCP flows that agree well with the existed reliable experimental data on normal and certain modes of deteriorated heat transfer, if significant influence of buoyancy and radical flow restructuring are absent. In addition, due to their relative simplicity and clearness, these methods made it possible recognizing certain important physical effects, which are useful for constructing advanced models of SCP-liquid thermohydraulics. For the more complicated cases than a flow in round vertical tubes, as well as for the case of rather strong buoyancy effect, more sophisticated prediction techniques must be applied.