Simulation Study On Boiling - Side Heat Transfer Of Shell - And - Tube Heat Exchanger

Due to its simple structure, high reliability, easy maintenance, low environmental requirements, shell-and-tube heat exchanger is widely used in the field of nuclear power, petrochemical industry, large power plant, refrigeration and air-conditioning, etc. However, the efficiency of the traditional heat transfer process without phase-change is relatively lower, has been unable to effectively deal with the contradictions of limited energy reserves and endless use. Under the that the energy are increasingly shortage, and their prices are constantly soaring, how to improve the most out of thermal efficiency of the shell-and-tube heat exchanger and strengthen the heat transfer has become very important problems faced by people. The shell-side boiling heat of the shell-and-tube heat exchanger is a kind of heat transfer process with phase-change. Compared to heat transfer process with no phase-change, the heat transfer efficiency of boiling heat is more efficient. Therefore, the research on boiling heat transfer has become a wider trend.But the studies on shell-side boiling heat of the shell-and-tube heat exchanger are slim and mostly concentrated in the single-phase flow research. The reason for this result is that immature multiphase flow theory and relatively complex heat exchange make it difficult to conduct simulation studies of the shell-and-tube heat exchanger and especially when coming down to the phase transformation, the multiphase flow simulation is becoming more difficult. Due to its powerful computing ability, FLUENT software makes it possible to conduct the complex heat exchange research of phase-change flow. The software’s own grid-making software which is called GAMBIT can draw high quality grid,and its solver has kinds of turbulence models and multiphase flow models. These features make it can be perfectly applied in the study on shell-side boiling heat of the shell-and-tube heat exchanger and can gain quite ideal results.In order to study the features of the flow and heat exchange of shell-side boiling heat of the shell-and-tube heat exchanger, This paper will preprocess the shell-and-tube heat exchanger by using the GAMBIT software to divide the grid, etc, and then, by adopting standard k-ε turbulence model and the mixture multiphase flow model and writing User-defined Function(UDF), calculate the boiling heat transfer of shell-side by using FLUENT software to get the scattergrams of two-phase flow, speed, pressure and temperature, etc, the results demonstrate that shell-side flow form the heat transfer dead zone at the back of the bow-shape plate and the generation of water vapor is concentrate mainly on the back and gathered upwards.hen the paper analyzes the effects of the performance and life of the heat exchanger and the corresponding improvement measures, which could supply references for the design and use of the shell-and-tube heat exchanger. Lastly, improvement and development of the shell-and-tube heat exchanger are discussed.