Research And Development Of External Oil Frying Heating Equipment Using Heat Pipe

Food is the most important thing for the people,and food safety is the first.Food safety is directly related to people’s health.The external heating fryer heats the frying oil through the external frying oil heater,and then transmits the frying oil to the subsequent equipment to fry food.At present,external heated fryers mostly use steam oil frying heat exchanger or heat transfer oil oil oil frying heat exchanger to heat the frying oil.This requires the addition of steam boilers or heat transfer oil boilers.This additional investment is undoubtedly a great burden on small food enterprises.Some also use vacuum frying technology.The food produced by vacuum frying has good quality.However,because its frying space needs to create a vacuum environment,the output is limited by the equipment cost.If you want high output,you need to invest a lot of money in the equipment cost.An external heat pipe type oil frying heating equipment is developed in this thesis.The equipment heats the heat pipe with the help of the high-temperature flue gas generated by gas combustion,and transmits the heat to the fried oil through the efficient heat transfer of the heat pipe.This heating method can ensure that there is no local large temperature difference in the heating process of frying oil,so as to ensure the quality of frying oil.The equipment development process adopts the method of combining experiment and numerical simulation.Firstly,the performance experiment of a single heat pipe is carried out.Determine the heat transfer power of a single heat pipe and the length of the evaporation section and condensation section of the heat pipe under the given heating and heat release conditions and the working temperature of the heat pipe.The results show that when the evaporation section of the heat pipe is 460 mm and the insulation section is 240 mm,and the working temperature is 200 ～ 220 ℃,it can not exceed the temperature and give full play to the maximum heat exchange capacity.On this basis,the prototype of heat pipe external oil explosion heating equipment is developed and its performance is tested.It is found that the working condition of the prototype made after the combination of heat pipes is different from that of the performance test of a single heat pipe.For example,the flue gas temperature around the heat pipe in the outlet area of the combustor in the evaporation section is high,the rear temperature is low,and the condensation section of the heat pipe in the oil tank is also different from that of the single heat pipe model test due to different oil temperature and flow rate.Therefore,it is necessary to optimize the prototype through digital simulation.The geometric parameters of the original machine are optimized by numerical simulation.The simulation results of the original model show that the heat exchange power of the heat pipes near the left and right ends in the oil tank,especially the heat pipes near the left(opposite direction of x-axis)is small,and the heat exchange effect is poor.The reason should be that the deflector is too short,so that the left and right heat pipes can not be effectively scoured.Therefore,the deflector is extended by200 mm in the optimization process.It can be seen from the convective heat transfer coefficient that the oil explosion velocity of the heat pipe at the end of the oil tank is lower than that at the inlet.At this time,it is necessary to increase the deflector,reduce the flow cross-sectional area of the oil explosion,improve the flow velocity of the oil explosion inside the oil tank,increase the convective heat transfer effect and improve the heat release power of the heat pipe.In addition,in order to solve the problem that the oil explosion at the top of the oil tank does not participate in heat exchange,the distance between the oil tank and the upper end face of the heat pipe is reduced.Finally,on the basis of optimization,the equipment prototype is redesigned,and the improved prototype is tested.The results show that during the working process of the improved prototype,the consistency of the wall temperature of the heat pipe group is good,and the expected purpose is achieved.