Flow and Heat Transfer Characteristics of Supercritical Nitrogen in Mini-Tube

Fluids with the state near the critical points-supercritical fluids show many tremendously strange characteristics, such as singularities in compressibility and viscosity, diminishing difference in vapor and liquid phases and so on which have attracted a lot of investigations both experimentally and theoretically for fundamental research. In the present study, experimental investigations of the heat transfer and fluid flow characteristics of supercritical nitrogen in a mini-tube of 2 mm in diameter and 250 mm in length are carried out, the effects of many influential factors on fluid flow and heat transfer are studied. Meanwhile, the numerical analysis of the fluid flow and heat transfer characteristics of supercritical nitrogen is also conducted by using FLUENT. It is found that the agreement between the experimental and numerical results is quite good and the further interpretation and discussion are carried out.