 # Adjust the internal heat transfer coefficient?

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• Last Post 17 October 2017
admin posted this 27 September 2017

How can I adjust the internal heat transfer coefficient?

cbhavsar posted this 17 October 2017

Heat flux to be supplied to the external wall as a boundary condition is available through the DEFINEPROFILE macro on the fluid-side wall. The heat transfer coefficient can be defined with the DEFINEHEATFLUX macro. This macro calculates the heat flux by the following equation. qid = cid + cid*CT(c0,t0) - cidF_T(f,t) - cidpow(FT(f,t),4) qir = cir + cir*CT(c0,t0) - cirF_T(f,t) - cirpow(FT(f,t),4) qid: convective heat flux qir: radiant heat flux To specify the heat transfer coefficient, one can be set the same value for the cid  and cid  within the UDF. For example, if you want to fix the heat transfer coefficient in a wall as 10 SI units, it can be realized as the follows. DEFINEHEATFLUX(flux,f,t,c0,t0,cid,cir) { if(THREADID(t) == wallid){ /* specify boundary heat transfer coefficient */ cid = 10.; cid = 10.; } } wallid is the zone ID of the wall you want to fix. Close 