Conjugate Heat Transfer

Aim:

To set up a conjugate heat transfer simulation through a pipe with a given input velocity.

Theory:

The Conjugate Heat Transfer problem involves the flow of air between two regions, a solid and a liquid region, where the fluid used here is gas.

Fig 1: Surface with edges with a base grid of 0.004

Fig 2: Outlet temperature

The temperature rises from 300 K and reaches a steady state at about 377 K at the end of the cycle. This is similar for the supercycle stage intervals of 0.01,0.02 and 0.03.

Supercycle stage interval:

1. 0.01:

Vid 1.1: Pressure animation

The pressure is high at the inlet and starts reducing as the flow passes through the tube and is lowest at the outlet in the fluid region. Whereas the pressure is low throughout the pipe in the solid region as no flow takes place.

Vid 1.2: Temperature animation

The variation in the temperature is quite evident in the fluid region whereas the temperature starts increasing at each time step and is the highest at the end of the cycle in the solid region. The heat transfer from the fluid region to the solid region is evident.

Vid 1.3: Velocity animation

The velocity remains constant in the solid region at its lowest as no fluid flow occurs. In the fluid region, however, there is slight variation in velocity but it is high throughout the cycle.

2. 0.02 & 0.03:

The pressure, temperature, and velocity are similar for these two supercycle intervals.

Vid 2.1: Pressure animation

The variation in pressure is higher in this time interval with it being at its highest at the inlet and lowest at the outlet. The pressure in the pipe almost becomes completely high at times due to the slight increase in the time interval.

Vid 2.2: Temperature animation

The temperature doesn\'t fluctuate that much as compared to to the 0.01 interval. The temperature in the solid region starts increasing as the cycle progresses.

Vid 2.3: Velocity animation

The velocity is low and constant in the solid region whereas it increases from the inlet to the outlet as the cycle progresses.

Conclusion:

The heat transfer between the two regions can be realized in this experiment. The outlet temperature variation is similar for all the three supercycle intervals whereas the flow of pressure, temperature and velocity are similar for the intervals 0.02 and 0.03. However, the flow for these three parameters varies for the interval 0.01.