how to get surface temperature of pipe at cross section using iso-surface

ashgun · May 26, 2013, 05:41

how to get pipe surface temperature of wall using isosurface ? for bulk temperature i created isosurface-> mesh -> then x cordinate -> tbulk temperature is 304 k but for surface temperature of wall its giving very low value 131k can anyone tell me how how to get surface temperature of pipe wall at cross section ? i am calculating local nusselt number plz tell me asap

misagh · May 26, 2013, 16:09

in order to get bulk temperature first you should create iso-surface:surface...iso-surface...grid...x or y coordinate.
now that you have created iso-surface you should do this process to get T bulk:report...surface integral...Mass-weighed average...Field variable(Temperature)...choose your surface...

to get the wall temperature do: plot...xy plot...axis function(temp.)...choose your favorite iso-surfaces that you created...plot and you can see the trend of the diagram of T.and if you want to see temperature as data points just tick the option WRITE TO FILE.don't forget to adjust plot direction(X0 Y1 OR X1 Y0 depending on your geometry)
BESTS

ashgun · May 26, 2013, 17:37

Thanx but still its showing bulk temp data how can i get surface temp. my pipe length is along x-axis i didn't get u

i want only wall temp at distance z=y=radius of pipe

ashgun · May 26, 2013, 17:41

can't i get directly surface temperature of wall at given iso-surface directly lyk bulk temp. so that it will help me to get local nusselt no. directly qflux/(ts-tb)

misagh · May 27, 2013, 05:39

no you cant get the wall temperature from bulk tempr. since it is mass-weighed average.ie. it has been integrated in the whole surface.

to get the wall temperature do: plot...xy plot...axis function(temp.)...choose your favorite iso-surfaces that you created...plot you can see temperature as data points just by activing the option WRITE TO FILE. save it and then open it with notepad and the temp. at y=z=cte=radius is the wall temp.

now you can use [q/delta T] for Nuselt Number.

ashgun · May 27, 2013, 17:31

thanx what is cte btw

misagh · May 28, 2013, 06:06

your qestion is what is cte?? it's constant.

ashgun · June 1, 2013, 19:29

bro i got answer for surface temperature we hv to creat iso surface at given section and choose wall as surface type then facet avg. of wall gives surface temperature directly

now i hv another problem i hv to provide constant heat flux, only on lower semicircular area of cylinder how to do it ?

misagh · June 2, 2013, 03:03

i am not sure if any other easier way to create a semi circular with constant heat flux BC is available or not, but in your geometry you can divide the circle in two semi-circular and use the BC constant heat flux for the lower semi-circle in Gambit or any other software that created your geometry.

May 26, 2013, 05:41	how to get surface temperature of pipe at cross section using iso-surface	#1
ashgun New Member abhi Join Date: Sep 2012 Posts: 11 Rep Power: 14	how to get pipe surface temperature of wall using isosurface ? for bulk temperature i created isosurface-> mesh -> then x cordinate -> tbulk temperature is 304 k but for surface temperature of wall its giving very low value 131k can anyone tell me how how to get surface temperature of pipe wall at cross section ? i am calculating local nusselt number plz tell me asap

June 1, 2013, 19:29	regarding udf for heat flux	#8
ashgun New Member abhi Join Date: Sep 2012 Posts: 11 Rep Power: 14	bro i got answer for surface temperature we hv to creat iso surface at given section and choose wall as surface type then facet avg. of wall gives surface temperature directly now i hv another problem i hv to provide constant heat flux, only on lower semicircular area of cylinder how to do it ?

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May 26, 2013, 16:09		#2
misagh Member misagh Join Date: Apr 2012 Posts: 64 Rep Power: 14	in order to get bulk temperature first you should create iso-surface:surface...iso-surface...grid...x or y coordinate. now that you have created iso-surface you should do this process to get T bulk:report...surface integral...Mass-weighed average...Field variable(Temperature)...choose your surface... to get the wall temperature do: plot...xy plot...axis function(temp.)...choose your favorite iso-surfaces that you created...plot and you can see the trend of the diagram of T.and if you want to see temperature as data points just tick the option WRITE TO FILE.don't forget to adjust plot direction(X0 Y1 OR X1 Y0 depending on your geometry) BESTS

May 26, 2013, 17:37		#3
ashgun New Member abhi Join Date: Sep 2012 Posts: 11 Rep Power: 14	Thanx but still its showing bulk temp data how can i get surface temp. my pipe length is along x-axis i didn't get u i want only wall temp at distance z=y=radius of pipe

May 26, 2013, 17:41		#4
ashgun New Member abhi Join Date: Sep 2012 Posts: 11 Rep Power: 14	can't i get directly surface temperature of wall at given iso-surface directly lyk bulk temp. so that it will help me to get local nusselt no. directly qflux/(ts-tb)

May 27, 2013, 05:39		#5
misagh Member misagh Join Date: Apr 2012 Posts: 64 Rep Power: 14	no you cant get the wall temperature from bulk tempr. since it is mass-weighed average.ie. it has been integrated in the whole surface. to get the wall temperature do: plot...xy plot...axis function(temp.)...choose your favorite iso-surfaces that you created...plot you can see temperature as data points just by activing the option WRITE TO FILE. save it and then open it with notepad and the temp. at y=z=cte=radius is the wall temp. now you can use [q/delta T] for Nuselt Number.

May 27, 2013, 17:31		#6
ashgun New Member abhi Join Date: Sep 2012 Posts: 11 Rep Power: 14	thanx what is cte btw

May 28, 2013, 06:06		#7
misagh Member misagh Join Date: Apr 2012 Posts: 64 Rep Power: 14	your qestion is what is cte?? it's constant.

June 2, 2013, 03:03		#9
misagh Member misagh Join Date: Apr 2012 Posts: 64 Rep Power: 14	i am not sure if any other easier way to create a semi circular with constant heat flux BC is available or not, but in your geometry you can divide the circle in two semi-circular and use the BC constant heat flux for the lower semi-circle in Gambit or any other software that created your geometry.