Research Of Key Technologies Of Thermal Conductive Composite Compact Plate-Shell Heat Exchanger

Aimed at the widely occurring corrosive environment and its rigorous requirement to equipments, a new efficient anticorrosive heat exchanger is developed. By using the theoretical analysis, finite element numerical simulation and experimental methods, some key technologies of thermal conductive composite compact plate-shell heat exchanger are researched. The achievements include:1. The high thermal efficiency of independently developed thermal conductive composite compact plate-shell heat exchanger may observably reduce the count of required equipments, and with the same processing quantity, its place is about 1/5 of the graphite tubes heat exchanger. It is especially applicable to the situation where there is a phase-changed medium, the pressure drop of core body is less than 5% of inlet. The plate-fin structure is credible not only under the work load of 1MPa, but also with a very little distortion, therefore, the heat transfer areas and coefficient are stable.2. Based on the existed experimental results and theoretical analysis, the strength mix-principle formula and estimating formula of thermal conductivity of short fiber reinforced composite are deduced, and the mathematic models are used to describe the effect of parameters on strength and thermal conductivity. By employing the parametric finite element analysis of ANSYS, the numerical study of the thermal conductivity of graphite filled PTFE composite is performed. In combination with the experimental results, the reference is provided to PTFE composite thermal conductivity design. The formulation of thermal conductive composite in the new design is confirmed and its mechanical performance and thermal conductivity are forecasted.3. By using the full parametric finite element numerical simulation, a series of data is collected, and the relationship between the stress and structure parameters of plate-fin is analyzed. The results show that the stresses in fin and partition are smaller than them obtained from experienced formulas, and the difference is greater along with the bigger m/t_f, especially in partition, there are notable differences. The new engineering calculation expressions of the stress of the partition and fin are given, and it shows that they are the effective supplement of existing design criterion.4. The effect of various spew geometry on stress distribution and maximum value in adhesive joints is investigated. The spew can change the location of the biggest stress and the law of stress distribution, and the presence of spews can reduce peak stresses and therefore increase the joint strength, however, is related not only to the presence of spew, but also to the shape and size of the spew. The adhesive joint with triangular spew has the minimum stress, and there is optimization design space. With the optimized geometry, there are three low component stresses, and the triangular spew is the easiest one to be obtained, therefore it is the choice.5. A series of optimization designs are executed to triangular spew, the results show that adhesive thickness gradually increases and angle decreases with the increase of partition thickness. Synchronously, when adhesive thickness is 0.3mm and angle is 30°, maximum stress values are lower whatever spew dimensions. This implies that if the joint is controlled in this size, the technical effect will be nice even through the joint is not the optimization design.6. The optimization design method based on CFD is discussed, the optimized guide shell is helpful to obtain the more symmetrical inlet velocity.7. To the seal plate with special hatch, by employing advanced material mechanics and elastic mechanics theories, the opening area and annulus area are studied and the influential factors are concluded, and the engineering associated model is presented. By means of 3D FEM and the path analysis in crucial area, the stress distribution of seal plate is acquired. By using the serial simulation results and advanced data processing and fitting technologies, the stress formula is obtained. The work will provide the reference to engineering application of new design.