Analysis Of Mechanism On Radial Heat-pipe Without Wick

Radial heat-pipe is applied to the growth of semiconductor material, standard blackbody, and temperature calibration and so on. It will be applied widely to industrial process equipment, such as heat-pipe economizer for the sulfuric acid plant and distillation heating furnace pipe for decompression device of oil refinery.Based on whether having a wick, radial heat-pipe is divided into two kinds. There are few reports about radial heat-pipe without wick so far. At present, what is concerned is economical efficiency. Economical efficiency of the productivity is enhanced because the process of fixing wick is avoided in the course of manufacture radial heat-pipe without wick. Experimental and theoretical research of radial heat-pipe without wick is performed in this paper. Heat transfer model and performance are studied and the major contents are as follows:(1) Coaxial glass annular tubes are applied as the radial heat-pipe of the visualization experiment. At various filling amount, heat transfer phenomena are observed .Water in the bottom of the radial heat-pipe is boiling and few change are found in the middle or top of the radial heat-pipe. There are water drops on the outer wall of the inner pipe, which is possibly the condensed vapor. So its heat exchange model is supposed. It includes two parts that the heat is transferred from the outer pipe to the work media, the boiling heat transfer of water and convection heat transfer of vapor. The heat in the heat-pipe is transferred to the cooling water of the inner pipe after the vapor is condensed on the wall of it.(2) Experimental platform of carbon steel-water radial heat-pipe without wick is set up. At first startup capability is studied and startup temperature is measured. In various operating conditions, from the collected temperature, the temperature in the bottom of the radial heat-pipe is almost the same, but the temperature of other locations change clearly. This is consistent with heat exchange model of visualization experiment. The total heat transfer flux, the total heat resistance of radial heat-pipe and boiling heat transfer flux are obtained. Heat transfer coefficient correlation of convection is presented in this paper.(3) Fluid controlling equations—mass, momentum and energy equations are deduced.Radial heat-pipe wall temperature is computed using the heat transfer coefficient correlation of convection imported from UDF in Fluent. Calculation results are compared with that of experiments. It is found that calculation results are higher than experiment data and the temperature grads are quite the contrary. Error includes two parts, the error between experiment data and actual data, the error between numerical model and actual model. Temperature and velocity distributing of interior steam are simulated and their mechanism are explained.