ÿþ<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd"> <HTML> <HEAD> <TITLE>Heat and Mass Transfer Lab - Research</TITLE> <!--#include virtual="menu2.inc"--> <BR> <TABLE WIDTH=90% VALIGN=TOP ALIGN=CENTER border=0 CELLSPACING=0 CELLPADDING=0> <TR> <TD HEIGHT=25 ALIGN=CENTER VALIGN=MIDDLE> <IMG HEIGHT=32 WIDTH=520 SRC="./Images/Bannerresearch520.jpg" border=0 ALT="Research"> </TD> </TR> </TABLE> <BR> <TABLE WIDTH=90% VALIGN=TOP ALIGN=CENTER border=0 CELLSPACING=0 CELLPADDING=0> <TR VALIGN=TOP ALIGN=LEFT> <TD ALIGN=CENTER> <H2> Overall Wall Mass Transfer Coefficient </H2> </TD> </TR> <TR VALIGN=TOP ALIGN=LEFT> <TD VALIGN=TOP ALIGN=CENTER> <IMG SRC="./Images/Shov-mass.jpg" Width=507 Height=540 border=0 ALIGN=CENTER style="margin-left: 20px;" style="margin-below: 20px;" ALT="overall wall mass transfer coefficient"> <BR> <P ALIGN=JUSTIFY> Our experiments showed that the true wall-region mass transfer coefficient Sh<sub>wf</sub> did not tend to zero as Re decreased. However, the literature experiments showed that Sh<sub>ov</sub> = aRe<sup>b</sup>, so that Sh<sub>ov</sub> was predicted to tend to zero as Re ’! 0. To investigate the different behavior of these parameters we calculated Sh<sub>ov</sub> from our data. The results are presented in the figure above. We see that log Sh<sub>ov</sub> varied linearly with log Re over the entire range of the data, in agreement with the literature correlations, and in contrast to the corresponding plots for Sh<sub>wf</sub>. The best fit to all the data simultaneously was found to be</P> <P ALIGN=CENTER><i> Sh<sub>ov</sub> = 0.56 Sc<sup>S!</sup> Re<sup>0.62</sup></i></P> <P ALIGN=JUSTIFY> The exponent on Re was in the range of the previous work, and the constant was slightly lower. It was not possible to determine a clear dependence on N from these data. So, our results for Sh<sub>ov</sub> confirmed those of the previous studies. </P> </TD> </TR> </TABLE> <BR> <TABLE WIDTH=90% VALIGN=TOP ALIGN=CENTER border=0 CELLSPACING=0 CELLPADDING=0> <TR VALIGN=TOP ALIGN=LEFT> <TD WIDTH=45% VALIGN=TOP ALIGN=LEFT> <A HREF="fbht1.html"> <IMG WIDTH=50 HEIGHT=22 SRC="./Images/backsm.jpg" BORDER=0 ALIGN=RIGHT ALT="Back"> </A> </TD> <TD WIDTH=10%></TD> <TD WIDTH=45% VALIGN=TOP ALIGN=LEFT> </TD> </TR> </TABLE> <BR> <TABLE WIDTH=100% border=0 CELLSPACING=0 CELLPADDING=0> <TD align=right> <font size=1> Last modified:<BR> Jan. 6, 2005 <BR> <ADDRESS><A HREF="mailto:agdixon@wpi.edu">agdixon@wpi.edu</A></ADDRESS> </TD> </TABLE> <!--#include virtual="end.inc"-->