<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type"> </head> <body bgcolor="#ffffff" text="#000000"> Dear Gunter & All, It was me who put the vertical heat channel, buoyancy-flow correlations into ESP-r (incl. the Bar-Cohen & Rohsenow correlation). All those correlations depart from the channel wall temperatures, then go to Rayleigh number(s), then to Nusselt and wall convection coefficient values.  The air velocity is dynamically calculated as function of the glazing temperature, which then influences the glazing temperature. I used/developed them for air gaps of a naturally ventilated window, with gaps of 2 and 4 cm. I haven't looked at the latest versions of ESP-r, but I guess that it shall be mostly unchanged in that part. The details are in my thesis, at sections 2.3, 4.3 and chapter 6. It is written in English and you can download it from: <a class="moz-txt-link-freetext" href="http://paginas.fe.up.pt/%7Evleal/VLfiles/Leal_PhD_Thesis.pdf">http://paginas.fe.up.pt/~vleal</a> I recommend that you use small time steps (1 or 5 minute) time-steps if you model this way. Kind regards, Vítor Pueltz, Gunter wrote: <blockquote cite="mid2417729F3416D511A27E0090273A963B010B08D9@smex01.mbbm.de" type="cite"> <pre wrap="">To the ESP-r fan club: Can anyone provide some informations about the Bar-Cohen and Rosenhow correlation for convective heat transfer coefficients in an open, vertical channel (only buoyancy driven air flow) ? Does this correlation take the air velocity within a channel into account ? Is the air velocity calculated according to the results of the air-flow-network ? The channel itself is a zone, which is linked with an air flow node .... What is the best approach for the htc in an open, vertical channel with intensive air flow (one side of the channel is very hot: it is the wall of a turbine) ...? Any comments are appreciated ! Best regards, Gunter -- Gunter Pültz Müller-BBM GmbH Robert-Koch-Straße 11 82152 Planegg Telefon +49 (0)89 85602 - 336 Telefax +49 (0)89 85602 - 111 <a class="moz-txt-link-freetext" href="http://www.MuellerBBM.de">http://www.MuellerBBM.de</a> _______________________________________________ esp-r mailing list <a class="moz-txt-link-abbreviated" href="mailto:esp-r@lists.strath.ac.uk">esp-r@lists.strath.ac.uk</a> <a class="moz-txt-link-freetext" href="http://lists.strath.ac.uk/mailman/listinfo/esp-r">http://lists.strath.ac.uk/mailman/listinfo/esp-r</a> </pre> </blockquote> </body> </html>