pipe flow problem with very high heat flux boundary condition imposed at wall
 

Hello everyone
I am simulating a three-dimensional pipe flow problem using air as working fluid under laminar flow regime in Ansys Fluent 18.1. The boundary condition applied as velocity inlet at inlet section, pressure outlet at outlet section and constant heat flux of 30000 W/m^2 at pipe wall. Only fluid domain is considered for this problem.

The problem occurred in solving the energy equation as it show error while iteration "temperature limited to 5000 K in various cells on zone 4 in domain 1".

The geometrical dimensions of pipe are diameter = 66 mm and length = 3 m. The inlet temperature of air is 300 K. I have used structured mesh of quadrilateral size and total element of 1.4 million cell. The orthogonal quality, aspect ratio and skewness are also in the appropriate range.

Can anyone please suggest why this error is ocuured?

Thankyou in advance