Experimental Study And Numerical Simulation Of Thermal Flow Field For Irradiation Box Of Low-voltage Cable Ultraviolet Cross-linking

Wire and cable plays an important role in the economic construction anddaily life, XLPE cable has become the largest varieties of power cables indemand. The comprehensive performance of the modified polyethyleneinsulation is significantly improved, which is widely used in power cable, controlcable, computer cable, etc. Ultraviolet crosslinking technology by ourindependent research and development with independent intellectual propertyrights is began to applied in polyolefin crosslinking methods in recent years, lessinvestment in equipment, convenient maintenance, energy saving and efficient,has the broad application prospect. The irradiation box is the core equipment ofthe ultraviolet crosslinking production lines and the place for ultravioletcrosslinking reactions. The internal temperature control of the irradiation box isthe key to ensure smooth and efficient ultraviolet crosslinking reactions. The heatis taken away from the high temperature wall by air forced convection, not onlyneed to reduce component temperature, but also must ensure that coolinguniformity, some parts can neither overheating, nor too cold. The design ofventilation scheme must meet the temperature control requirements of differentpart at the same time.Firstly, wind velocity measurement experiment of ventilation ducts isconducted using a hot wire anemometer, and record the fan motor rotationfrequency of the ventilators, obtain the wind velocity of ventilation ducts of twoirradiation box ventilation structures under different operating conditions, theaverage flow rate data of pipe can provide boundary conditions for the flow fieldnumerical simulation of the irradiation box. Secondly, the three ventilation scheme physical models of the irradiationbox are established, using the FLUENT software to simulate the cooling airvelocity and pressure distribution, the impacts of equipment structure changes onflow field are analyzed with special focus on the convection cooling effect ofinsulation layer, ultraviolet mercury lamps and reflectors. Obtain the physicvalues of flow field which are difficult to measure under the experimentalconditions, provide a reference for the optimal design of irradiation boxventilation scheme through the comparison of the flow field data of differentventilation schemes.Finally, this dissertation gives the simulation of unsteady-state temperaturefie ld for the low-voltage cable and high-voltage cable in cross section by usingFLUENT DO model, validates the accuracy of the model, and analyzes thetemperature distribution of the cable section and the change trend of temperatureof insulation, inner shielding and conductor cores. Within the low-voltage cable,the temperature change of insulation layer caused by convection and radiationheat transfer is not significant; the effect of the heat transfer between conductorand insulation on the temperature distribution of the insulation layer plays aleading role. Within the high-voltage cable, radiation and convection andconduction effect temperature distribution of the cable cross section together.