The Research And Development Of The New Heat Exchanger With Different Diameter Tubes And Holding Structure

The heat exchangers are the process equipment widely used in a great deal of industries such as petroleum-chemical engineering, heating and power, nuclear power, metallurgy, environmental protection, etc. In oil refining and chemical engineering equipments, the heat exchangers are 40 percent of the total. Along with the high-speed development of industry, being hard up in energy sources and good-sized equipments, the research on new type of the efficient and energy-saving heat exchangers is remarkable. In the paper, a new model of the heat exchanger with different diameters tubes and holding structure is presented, which has the notable characteristics of high efficiency, low hydro-resistance and anti- vibration, and prolongs the utility life accordingly.new heat exchanger with different diameter tubes and holding structureThe main research works is as follows:1. The heat exchanger with different diameters tubes and holding structure is first showed. The layout method of tubes with different diameters is considered in heat exchangers. The heat transfer area is increased 30 percent than the traditional heat exchangers'.2. The model of the "five-tube unit flow passage" is introduced. Three-dimensional numerical simulation of the coupling of flow field and temperature field of single-phase turbulent flow in shell side of the new exchanger is performed. And Compared with the results of experiments, it is assured that the numerical simulation model can perfectly reflect the changes of the flow and heat transfer of fluid in the shell side of the new heat exchanger. Studied the effects of the flow and heat transfer relation on the changes of structure parameters, the nondimensional criterion equations of heat transfer and pressure drop about the heat exchanger shell side are conducted. It provides the theoretical foundation for further optimized design of the new heat exchanger.3. The Field Synergy Principle is developed in the complicated structure. The figures of average field-synergy angles in the shell side are obtained using user-defined programs. The effect of the angle between the vector of velocity and the vector of temperature gradient impacted on the heat transfer ability of fluid is analyzed by numerical simulation. The calculation formula of the synergy angle of shell side in the new exchanger is given firstly, and it goes well with the numerical solution. Through detailed analysis, it can be seen that the new structure has good field-synergy effect.4. Take into account the effect of heat transfer, the reasonable space between rod baffles is obtained. By comparing with baffles structure, the natural frequency tube bundle with new holding support structure is increased remarkably. Thus, the anti-vibration function of the new structure is enhanced, and the service life is increased.5. The mechanism of flow-induced vibration of the heat exchanger is analyzed. Vortex shedding frequencies at different structural parameters and flow velocities is obtained firstly, the figures of St-Re and St-P/t that can be used in engineering field is drawn and used to calculate the characteristic of the vortex frequency under the new structure work condition.6. In the process of intensity calculation of tube sheets based on the flat plate theory, the solution of effective elastic constants of tube sheets with layouts of non-square and non-equilateral-triangular holes hasn't been studied home and abroad. In this paper analytic...