Research And Design Of A Novel Tubular Instant Heating Heat Exchanger

Since intelligent bidet seat appeared in China,the people’s daily life quality is further improved. The instant heating type heat exchanger which is one of the core component of intelligent bidet seat, can heat cold water to become comfortable temperature quickly and support long time washing. Therefore, the heat exchanger performance greatly affects the use comfort of intelligent bidet seat. At present sold intelligent bidet seat products in the market, which have problems as follow:the heat exchanger efficiency is not high enough; the high temperature of heater surface affects use lifetime; the fluctuating water temperature, which make the body have sometimes hot and sometimes cold discomfort feeling when they are washing; at the same time heating cold water to become comfortable temperature of warm water need a long time, etc. Because of current heat exchanger having problems, such as heat transfer efficiency is not high enough, water temperature fluctuation high, and long heating time, This thesis makes a ceramic heat exchanger to improve design and offer a new type structure of heat exchanger which is optimized designed through the parameters of structure.This thesis analyzed the technology status of existing high power heat exchanger. Based on knowledge of heat transfer, a redesign of existing heat exchanger to improve the product was performed. This thesis presented a new type heat exchanger, selecting swirling flow path section height, straight line flow path section height, spiral flow path section length as design parameters; Fluid flow, heat transfer process and the heater surface temperature distribution of heat exchanger simulated and calculated through using FLUENT software, researching design parameters impacting on the instant heating type heat exchanger performance. Tooling instant heat exchanger samples using CNC, testing heat transfer performance of real sample, by comparing the practical test results and simulation analysis results, verify the article established the performance of heat transfer numerical simulation model of heat exchanger accuracy. Finally by the swirling flow path section height, straight line flow path section height, spiral flow path section length as design parameters and making orthogonal list, because the calculation can only be obtained by using orthogonal list parameters of Reynolds number, also using the FLUENT software to simulate the parameters which was carried out by the orthogonal list calculation to analyze the surface temperature of the heater. The lowest temperature of the surface of heater as the optimization goal, so as to obtain the instant heating type heat exchanger design of optimum parameters; The characteristics of this thesis are:Aiming at the deficiency of existing products, through improving the structure of heat exchanger, changing the natural convection heat transfer to be the forced convection heat transfer mode, and enhance mutual mixed effects of different temperature water, analysis and parameter optimization of heat exchanger design method for the numerical simulation analysis, so that the heat exchanger of thermal efficiency increased; Considering the constraints of existing when determining the range of design parameters optimization, in order to avoid that after the parameter optimization completed, when was mass production finding that the optimized parameters can not be used, need to restart numerical analysis; Doing real test with real samples of CNC processing, to verify accuracy reliability of the heat transfer numerical simulation analysis model. This kind of product improvement and optimization design method can effectively save the cost of design improvement, has the important guiding significance to optimize the design of heat exchangers of different styles of enterprises in future.