In this study, the numerical analysis on the performance of solar chimney is done using buoyantBoussinesqSimpleFoam.
The schematic of problem is displayed below.
The grid is created with blockMesh. A fabulous feature in blockMesh which can be used to calculate mathematical paramters is #calc . look following examples:
1- theta is 30 degree, convert degree to rad :
2-use sin(theta) or cos(theta) functions :
for simulation of 2d axisymmetric problem in OpenFOAM, special treatment is needed. The angle between planar front and back patch is less than 5 degree and the type of BC is considered wedge. The final grid is shown below:
There is a turbine in solar chimney. It is modeled implicitly via fan BC. The fan boundary employs a pressure jump or drop consistent to the velocity crossing the patch. The fan is a sub-function of cyclic boundary condition. In order to create a cyclic BC along air flow, the OpenFOAM utility createBaffleDict is employed. The position of cyclic boundary is shown in above figure (fan_half0).
The convection boundary condition is taken into consideration for the roof of collector. This BC is employed with the aid of groovyBC as follow:
type groovyBC; variables "q=800;h=3;Tinf=300;Cp0=1.0035e03;rhoAir=1.127;kair=kappaEff*rhoAir*rhok*Cp0;"; valueExpression "q/h+Tinf"; gradientExpression "0"; fractionExpression "1/(1+kair/(h*mag(delta())))"; value uniform 300;
The temperature and pressure contour is shown below:
extra pictures from another simulation:
fan BC in OpenFOAM-v5 does not support negative pressure jump, so groovyBCJump is another option.
1- Xu, G., Ming, T., Pan, Y., Meng, F. and Zhou, C., 2011. Numerical analysis on the performance of solar chimney power plant system. Energy Conversion and Management, 52(2), pp.876-883.