Reverse Cross Flow Plate Heat Exchanger, ANSYS Fluent CFD Simulation Training

Description

Problem Description for Reverse Cross-Flow Plate Heat Exchanger CFD Simulation

The present problem is going to simulate a plate panel of a cross flow heat exchanger. This heat exchanger consists of two special flow channels such that the air flows from one side of the central panel and the solute flow to the other but in the opposite direction to the airflow. In general, this panel is related to one of the two panels in the soluble and airflow closed cycle. The fluids used in the present model include air and ethylene glycol, or (CH2OH). Their thermophysical properties are manually defined in the ANSYS Fluent software.

Ethylene glycol is a colorless, odorless, low-volatility, low-viscosity material whose properties are defined as temperature-dependent polynomials. By the way, since the hot and cold flows do not integrate within the heat exchanger, there is no need to use a Multiphase flow module. On the other hand, a separator plate is used as an interface. The liquid has a higher temperature than the airflow. The purpose of the present study is to investigate the fluid behavior and heat transfer in the heat exchanger and to evaluate the performance of it based on the Number of Transfer Units (NTUs).

The Assumption for Reverse Cross-Flow Plate Heat Exchanger CFD Simulation

Several assumptions used for the present simulation:

The simulation is Steady-State and the solver is Pressure-Based. Also, the gravity effect is ignored.

Geometry and Mesh of Plate Heat Exchanger

The 3-D geometry of the present model is designed by Design Modeler software. The present model is a heat exchanger panel with two flow paths, such that, on the one hand, the hot liquid flow and on the other hand, cool airflow in the opposite direction to the liquid flow. The outer walls also act as insulators.

The meshing of the present model is performed by ANSYS Meshing software. The mesh is unstructured and the element number is 155,000. The cells are smaller and more accurate near the wall boundary.

CFD Simulation

Summaries of the problem definition and problem-solving steps are summarized in the table:

Models
Laminar		Viscous model
on			Energy
Boundary conditions (plate heat exchanger)
Velocity inlet		Inlet type
2.731074 m.s-1	velocity	air
302.5 K	temperature
0.026125 m.s-1	velocity	liquid
310 K	temperature
Pressure outlet		Outlet type
0 Pa	gauge pressure	air
0 Pa	gauge pressure	liquid
wall			Walls type
insulated		all outer walls
coupled		all inner walls
Solution Methods (plate heat exchanger)
Simple			Pressure-velocity coupling
second-order upwind		pressure	Spatial discretization
second-order upwind		momentum
second-order upwind		energy
Initialization (plate heat exchanger)
Hybrid		Initialization method

You can obtain Geometry & Mesh file and a comprehensive Training Movie that presents how to solve the problem and extract all desired results.