Experimental Study Of The Effect Of Nonuniformity Of Fiber Bundles On Shell-Side Transfer Performance Of Membrane Modules

Hollow fiber membrane modules are broadly used in the separation engineering technology as equipment component with the advantages of high specific surface area, large operating range, simple structure and low cost. However, due to some reasons such as manufacture, fiber bundles are randomly distributed in the shell-side. The nonuniformity of fiber bundles results in the complicated characteristic of the flow pattern in the shell-side. Additionally, some effect factors such as fibers are pliable and cross-flow exists in the areas that are closed to the input and output ports. Therefore, there are differences between researchers about transfer correlations of shell-side. By now, people have not reached an agreement about law of how the nonuniformity of fiber bundles affects the transfer performance of shell-side in the membrane modules yet. In order to study this difficult problem thoroughly, in the light of heat and mass transfer analogy as well as temperature measurement is more accurate than concentration measurement, and could achieve real-time monitoring. So we conceive the idea that use stainless steel rather than hollow fiber to build the heat transfer test device, experimental study the effect law of nonuniform arrangement of tube bundles on the transfer process of shell-side.These studies were carried out in three different test devices with packing density of10%,20%and30%, respectively. The cold water flowed in the tube-side, with Reynolds number Re was between91.42and1544.85and temperature was in the range from16.90℃to30.31℃. The fluid flowed in the shell-side was pure water, glycerol solution with50%,75%,90%mass concentration of glycerol and pure glycerol, respectively. The Re number of shell-side fluid was from0.00031to500.05, the temperature was in the range from21.94℃to49.99℃. After carrying out a series of experimental studies, reached the following conclusions:(1) Firstly, employed pure water as shell-side fluid (Prandtl number Pr is approximate constant), a series of experimental studies indicated that:when packed density is10%, the Nusselt number Nu is linear with Re of the power0.599; when the packed density is20%, the Nu is linear with Re of the power0.566; when the packed density is30%, the Nu is linear with Re of the power0.507.(2) Secondly, employed50%,75%,90%glycerol solution and pure glycerol as shell-side fluid, a series of experimental studies indicated that:when the packed density is10%, the Nu/Re0599is approximate linear with Pr of the power0.611; when the packed density is20%, Nu/Re0.566is linear with Pr of the power0.485; when the packed density is30%, Nu/Re0.507is linear with Pr of the power0.423.(3) Thirdly, the heat transfer correlation was drawn to apply to the conditions that packed density is between10%and30%, the Re is between0.00031and500.05, the Pr is between3.66and8131.15, respectively. The correlation as follows(4) Finally, the similar prediction tendency of this paper with some researchers is that the transfer coefficient decreases with an increasing packed density.