R&R Consult helped analyze and optimize the design of the Mosman Bulk Solids Heat Exchanger (BSHE). The BSHE is used for cooling or heating free- flowing bulk solids, via a pillow plate heat exchanger. In order to reduce the risk of caking in the pillow plate bank, dry air is injected at several horizontal planes and then flows upwards through the pillow banks and bulk solids. The air is injected via air inlet manifolds and distributed through multiple nozzles/studs in each manifold. The nozzles are welded on the manifolds, which is a costly manufacturing process.
R&R Consult helped optimize the design of these manifolds by using Computational Fluid Dynamics (CFD). The objective was to achieve a uniform air distribution while minimizing pressure drop and manufacturing costs.

Mosman Bulk Solids Heat Exchanger
Path lines from distributor

 

 

 

 

 

 

 

 

 

The simulation process saw interesting meshing challenges, e.g. a full geometric discretization of all nozzles in the inlet manifold. This provided data concerning individual nozzle flow rates, and was used to minimize flow variation in the longitudinal direction of the manifold, while providing information regarding manifold pressure drop.

We significantly optimized the original design based on empirical design equations regarding manifold design and several state of the art numerical simulations. The final design yielded considerably reduced manufacturing costs. Furthermore, we established an optimum nozzle number/diameter combination in order to minimize flow variation in the nozzle row and generate the necessary flow uniformity inside the heat exchanger.

Flow distribution in manifold
Velocity through distributor
Flow uniformity, variation ± 9% from mean

 

 

 

 

 

 

 

 

 

 

The updated manifold design not only meets the prerequisites for efficient demoisturization. It also keeps the injected air from interfering with the product flow and considerably reduces manufacturing cost.

The case served as another example of combining fluid mechanical experience, knowledge and CFD for cost-efficient design analysis and optimization.