We have 14" turbine extraction bottom nozzle.Line expands to 20".Line is of CS and temp 353.4 deg c as operating temp.We have horizontal strut in z direction on this vertical line portion.Disp at nozzle in Z direction is zero given by vendor.At strut location supporting arrangment is achieved by horizontal shoe and strut to the bottom of the shoe.
Now at this strut if we model half OD with pipe temp, obviously it gives unfavorable results.
Question is if it is correct to model half OD with temp at support location to simulate radial expansion of pipe? As linear and radial expansion of pipe are different.Also we are not considering stiffness and radial expansion of the nozzle.Is CAESAR is capable of simulating radial expansion in this way?
Also is it nessesary to consider radial expansion at support location for this sensative case?

Yes, CAESAR "can" analyze radial deflection, but you have to do the math manually.

RH = RC(dT•alpha+1)

dR = RH-RC

dL = dR

dL = L•alpha•dT*

RH = Radius while hot
RC = Radius while cold
dT = actual change in temperature
alpha = coefficient of thermal expansion
dR = change in radius
dL = change in length of equivalent straight "pipe"
L = length of straight "pipe" = RC
dT* = fictitious temperature gradient to achieve equivalent thermal growth

If you are going to go to this effort, however, you should likely also run an FEA to get the rigidity of the pipe. Nozzlepro can analyze rigidity of the connection, provided material, dimensions, pressure, and temperature.
More pressure = less flexible. Use max pressure, or you do so at your own risk.
Hot = more flexible. Use ambient temperature, or you do so at your own risk.

Connect radial "pipe" via CNODEs to the center of actual pipe.