Mass flux enhancement using spacer filled channels in direct contact membrane distillation

This paper describes the effect of spacers on mass flux enhancement for dir ect contact membrane distillation (DCMD). A novel model is proposed which c an predict how mass flux increases when spacers are used. The model was der ived for the case where heat transfer coefficients on both sides are equal, bulk temperature differences are less than 10 degreesC, and distilled wate r is used as feed and permeate solutions. Heat transfer correlations for sp acer filled channels, obtained from an analogy between heat transfer and ma ss transfer, were used in this work. The predictions showed good agreement with the experimental results. The effect of spacers on the temperature pol arization is demonstrated. A novel analysis is used to calculate the temper ature polarization coefficients, which approach unity in spacer filled chan nels. (C) 2001 Elsevier Science B.V. All rights reserved.