I have a cylindrical geometry as shown in image. The gas is entering through inlet at a known mass flow rate and pressure at room temperature. The inside of the cylinder is at a high temperature. The gas is entering the chamber, getting heated and exiting through outlet. How to calculate the pressure inside the cylinder wall? As for convection heat transfer between the cylinder wall surface and heated gas how to calculate the convection heat coefficient?
And what happens to the gas flow behavior (temperature, velocity, pressure) when it enters from small cross section (room temperature) area to a bigger cross section area (higher temperature)?
If the box is a furnace and gas is burning in it, or the wall is electrically heated, then the pressures are entirely determined by the flowrate and the inlet & outlet areas. The heat transfer at walls is calculated by standard, traditional formulae like Dittus-Boelter etc as appropriate. This is elementary but usually adequate.
Thank you Jack Broughton
There is a heated source (Biomass) inside the cylinder which is generating the heat. The gas is flowing inside to keep an anaerobic environment inside so the chemicals do not interact. As the gas flows I assume there is forced convection happening. There are empirical relations for flow inside a circular tube like Dittus-Boelter as you mentioned. Is it also applied for the cylinder reactor i have? As the gas is entering from a narrow channel to a bigger area of cylinder.
It is difficult to give too much detail here, proper analysis requires a consideration of what is actually occurring in the vessel. I was assuming that it was a hot gas, such as in a heating-furnace or boiler and that convective heat transfer dominated. If the reactor has solid material in it the considerations are totally different, .and radiative heat transfer will be very significant, (often the main transfer). The analysis of developing flows such as after an expansion needs more consideration also, D-B equation is for developed flow.
please Follow the journal name: Internal Combustion Engine Heat Transfer and Wall Temperature
Modeling: An Overview.
Source:Archives of Computational Methods in Engineering
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