Rotary Heat Exchanger, Effect of Mass Flow Rate on Heat Transfer Coefficient CFD Simulation, ANSYS Fluent

Description

In this project, the simulation of a 2D rotary heat exchanger is performed. The rotary heat exchanger, also known as a rotary regenerator, is a type of heat recovery system that recovers heat from a hot gas stream. This equipment is commonly used in various industries, including power generation and HVAC systems, to improve energy efficiency. The simulation model developed here aims to provide an accurate representation of the thermal performance of a 2D rotary heat exchanger. The model is based on fundamental principles of heat transfer and fluid dynamics, and it can be used to predict the performance of the exchanger under various operating conditions.
The geometry of the heat exchanger is designed in Design Modeler software. The model consists of 2 regions. One is dedicated to the hot fluid and the other one is designed for the cold one. Next, the model is meshed in ANSYS Meshing software. A structured grid is generated and the total number of elements is 86,598.

Methodology

The aim of the study is to study the effect of mass flow rate on the heat transfer coefficient. Four different mass flows are studied including 0.02, 0.04, 0.06 and 0.08 kg/s. The hot Co2 with 700°C temperature flows into the hot domain and on the other side, cold water vapor with 30°C flows. Due to symmetrical physics, only half of the heat exchanger is modeled and instead, the axisymmetric boundary type is used. The rod inside is rotating with a constant rotational velocity of 100rpm. Also The Standard k-epsilon model is used to describe turbulence of the flow.

Conclusion

After the simulation process, velocity and temperature contours are extracted. In order to study the effect of mass flow rate on heat transfer, heat transfer coefficient is reported in each case. The following table represents the correlation between mass flow and heat transfer. As the data indicates, even though the mass flow rate increases linearly, the heat transfer demonstrates non-linear behavior.