Dear pillai,

I suppose you were looking for something like this

Temperature distribution profile for the pump standby line you can predict well by using any of the standard FEM/CFD analysis software like Ansys.For example in Ansys you can solve this problem by usisng conjugate heat transfer method.

1)Define your model from the branch point to the pump nozzle with material thermal conductivities(Atmospheric Air+Insulation+Pipe+fluid)for steady state thermal analysis.

2)Define boundary condition as follows

a)At branch point boundary specify operating temperatre as a constant temperature boudary condition.
b)At Surface of pipe/Insulation define it as adiabatic if insulated othewise in case of un insulated and open to atmospher define a convective heat transfer coefficient of 5~10 W/m2K.You can also model atmospheric condition by defining its properties.
c)In case your line is partially filled.This effect you can consider by modelling the fluid upto that level.
d)Specify fluid velocity at the branch point and end point equal to zero.

With these set of boundary condition the software will calculate heat flux and convective heat transfer coefficient at the fluid-solid boundary and will give temperature distribution in the entire model.
I hope this will be of information to you.
If you want simplified mannual calculation then I can send you a copy.

You can solve this problem by simlifying it and making some meaningfull assumsions.

1)Flow through the total crossection of the pipe
2)One dimentional steady state heat conduction trough fluid and metal pipe.

After taking actual values of variable for this case you will be surprised to know that the temperature will saturate to ambeint value after say 400 mm from branch point in your case.

I suppose this exersise you can do yourself.If you want me to show you this I will explaine you latter.

Therfore I see there is absolutely no need to go for calculating temperature profile in the stand by line of pump or any other such instance.

All the three possible cases for defining temperature in standby line disscussed previously are practised in all measure companies.

Regards,

Aslam