Research On Length Of Periodic Fully Developed Section And Flow Dead Zone In Shell Side Of Shutter Baffle Heat Exchanger

As the major energy-consuming equipment in energy industry, shell and tube heat exchanger’s level of heat transfer performance directly determines whether the production process can be carried out smoothly, and the level of production costs. Thus it can be seen develop new and high efficiency heat exchanger had fully significance of society and economy. The method which integrates numerical and experiment was adapted to research on flow and heat transfer in shell-side of the Shutter baffle heat exchanger in the paper. The following main achievements and innovations were obtained.(1) The characteristics of fluid flow and heat transfer in the shutter baffle heat exchanger were numerical studied. In the numerical simulations, the3D whole entity model was adopted to reveal the characteristics of fluid flow and heat transfer in shell side in detail. Three mainly characteristic of pressure gradient, dimensionless temperature and fluid velocity contours are selected to ascertain the length of periodic fully developed section. The influent of fluid velocity in the shell side and shutter baffle assembly modes of was analyzed. It was concluded that fluid flow and heat transfer are periodic in the middle section between the third shutter baffle from inlet and the first shutter baffle from outlet for the concurrent assembly modes, and fluid flow and heat transfer are periodic in the middle section between the second shutter baffle from inlet and the first shutter baffle from outlet for the symmetrical assembly modes. The length of periodic fully developed section of fluid flow and heat transfer is independent of the fluid flow rate in the shell side.(2) In order to understand the distribution and size of dead zone in shell side of Shutter baffle heat exchanger, the residence time distribution (RTD) data was obtained and used to analysis by using CFD code FLUENT in this paper. It is concluded that the size of flow dead zone in shell side of shutter baffle heat exchanger is reduced with increase of Reynolds number. The distribution and size of flow dead zone are effected by assemble types of shutter baffles. When the shutter baffle is symmetrical arranged, the size of dead zone in shell side was larger than that of co-rotating. At the same Reynolds number, the size of flow dead zone in shell side of shutter baffle heat exchanger is less than that of baffle plate heat exchanger. When Re=5000\Re=10000and Re=15000, the dead zone in shell side of shutter baffle heat exchanger with shutter baffle symmetrical arrangement are respectively59.23%、49.08%、46.06%of that in baffle plate heat exchanger, and the dead zone in shell side of shutter baffle heat exchanger with shutter baffle co-rotating arrangement are respectively29.94%、25.32%、19.80%of that in baffle plate heat exchanger.(3) The test-bed was carried out to test the characteristics of fluid flow in the shell-side of shutter baffle heat exchanger. LDV testing program was used to test fluid velocity in the shell-side. The numerical simulation conditions and models were established the same as the experiment to verify the simulation method chosen in this paper was feasible.