Conjugated Heat Transfer (CHT) in Plate Heat Exchanger CFD Simulation

Description

Plate Heat Exchanger CFD Simulation (Viscous Heating, CHT), ANSYS Fluent Training

Description

A plate heat exchanger is a kind of heat exchanger that consists of parallel series plates with metal plates in the middle to exchange heat between two fluids. The fluid flows through the space between two adjacent plates. This is the advantage of a Plate Heat Exchanger over conventional heat exchangers in that the fluids are exposed to a larger surface area.

In this project, four solid plates are modeled while four pipes are placed at the corner of the plates. The fluid (water) flows through the pipes at the same velocity and at different temperatures (20 & 40 Celsius) in reverse directions.

The geometry of the solution is designed in Design Modeler software, while all the solids are from one single part. The solids are 2*2m, and their thickness is 0.2m; the pipe’s diameter and length are 0.2m and 1.1m, respectively. Ansys meshing software is used for generating meshes of the solution. The elements are unstructured, and the number of elements is 2216379.

This CFD project is the 2nd episode of the ANSYS Fluent General Training Course.

This CFD project is the 4th episode of the Heat Transfer Training Course.

Methodology: Plate Heat Exchanger CFD Simulation

The pressure-based solver has been employed due to the incompressibility of the fluid. Also, the simulation is independent of Time, so it has performed in steady state form. Moreover, the gravitational effects are ignored. There is convection between water and pipes and conduction in the solids, transferring heat all over the domain. So, Conjugated Heat Transfer (CHT) was studied.

Conclusion

At the end of the solution process, two-dimensional contours and vectors related to water pressure, temperature, turbulence kinetic energy, and velocity are obtained. As depicted, water flows through the pipes with 200k and 400k as a symbol of high and low temperatures in opposite directions.

The very first heat transfer method is convection which is between the fluid and pipe walls. Then it is the conduction turn. The heat that is given from the water transfer inside the solid due to the conduction phenomenon.

The temperature gradient via contour lines is visible in the figures. It should be noted that fluid velocity is an important parameter to affect heat transfer. The more velocity of the water flow, the more convective heat transfer.