Great effort! you know you can perform quite nice simulations with pressure vessels like this. I have performed one of the thermomechanical analysis here: https://www.simscale.com/projects/ahmedhussain18/structural_.
First since it was a structural analysis, I meshed it using an Automatic tetrahedralization with moderate mesh refinement. Since it’s a pressure vessel, it makes more sense to do a thermostructural analysis in order to see the stresses formed inside this vessel both due to internal pressure and temperature. Therefore I selected “Uncoupled thermomechanical analysis” and steady-state due to simplicity considering that we are simulating the final response.
I than defined steel as a material for the vessel. I applied the pressure and temperature of 1 MPa and 573.15 (300 °C) repectively on the internal surfaces while keeping the vessel constrained from below, sides and top portion. I also applied the convection due to outside air to the external surfaces. I ran the simulation on 4 cores and it just took 1 minute to complete.
The figures below show the results of temperature, heat flux and vonMises stress respectively. The geometry deformation is scaled by 10 times here to show a little distortion. In last figure, through a cutout one can see how the vessel is deformed from top and bottom. One can apply more pressure and internal temperature to see more deformation. As a next step, you can also perform a transient analysis with increasing internal pressure and temperature with respect to time. For this you can have a look at: https://www.simscale.com/projects/ahmedhussain18/pressure_vessel_-_thermostructural_analysis_1