Effect of fluidized bed material at different Temperatures on the wear of the immersed metal surfaces


AbstractFluidized beds are used to increase heat transfer coefficient in heat exchangers. Usually the bed material is from sand (silica, Alumina…etc.). During the use of the bed, the sand particles collide with the submerged surface at different velocities.In this work, the effect of fluidized bed material on the metal surface submerged in it, and metal removed by wear at different air temperature was studied. It was found that the metal removed is very small because the velocity of sand particles is very small. This shows that heat exchanger, in which the fluidized bed is used, has ability to clean the submerged metal surface by it self. Results also showed that Aluminum was faster and more affected by fluidization than other metals used, for the same working period (48hr), the weight lost by Aluminum was 0.5 % while that for brass and low carbon steel were 0.005 % and 0.0042 % from the original weight respectively.The removed metal increased when the fluidized bed temperature was raised. The weight lost at last 8 hours period, by; Aluminum was 0.9 % and that for brass and low carbon steel were 0.007% and 0.006% from the original weight respectively.Experimental correlations of piece weight and working hours, and piece weight and fluidized bed temperature were proposed.Key words: heat transfer – heat exchanger - fluidized bed – wear of metals.