Vertical Heat Exchanger, CFD Simulation Ansys Fluent Training

Description

Vertical Heat Exchanger Description

The present simulation is about heat transfer in a vertical heat exchanger via ANSYS Fluent. A Heat exchanger is an industrial equipment whose main task is to heat transfer between its hot and cold sides. In this project, a vertical shell and tube heat exchanger are modeled.

The fluid used in this heat exchanger is liquid sodium. Sodium flow with a temperature of 900 K and a velocity of 1.5 m / s inside the helical tubes moves from the top of the heat exchanger to the bottom.

Sodium flow with a temperature of 400 K and a velocity of 1.5 m / s inside the cylindrical shell of the heat exchanger moves from down to the top.

The thermophysical properties of liquid sodium are defined as a function of temperature. Thus, density, specific heat capacity, thermal conductivity, and viscosity change at different temperatures.

Geometry & Mesh

The present geometry is designed in a 3D model via Design Modeler. The computational zone is the interior space of a heat exchanger. This heat exchanger is shell and tube type; It consists of a vertical cylindrical shell with a spiral tube inside.

The mesh of the present model has been done via ANSYS Meshing. Mesh is done unstructured, and the number of production cells is equal to 640618.

Set-up & Solution

Assumptions used in this simulation  :

• Pressure-based solver is used.
• The present simulation is steady.
• The effect of gravity is ignored.

 

Models
Viscous		k-epsilon
	k-epsilon model	RNG
	Near-wall treatment	standard wall function
Energy		On
Boundary conditions
Inlet (shell)		Velocity Inlet
	velocity magnitude	1.5 m.s-1
	temperature	400 K
Inlet (tube)		Velocity  Inlet
	velocity magnitude	1.5 m.s-1
	temperature	900 C
Walls (inner)		Wall
	wall motion	stationary wall
	thermal condition	coupled
Walls (outer)		Wall
	wall motion	stationary wall
	heat flux	0 W.m-2
Outlet (shell)		Pressure Outlet
	gauge pressure	0 pascal
Outlet (tube)		Pressure Outlet
	gauge pressure	0 pascal
Methods
Pressure-Velocity Coupling		coupled
	pressure	Second-order
	momentum	Second-order upwind
	energy	Second-order upwind
	turbulent kinetic energy	First-order upwind
	turbulent dissipation rate	First-order upwind
Initialization
Initialization methods		hybrid

Vertical Heat Exchanger Results

After calculation, 2D and 3D contours related to temperature, pressure, and velocity are obtained. The contours show that heat transfer occurs between the shell (with lower temperature) and the tube (with higher temperature). In this way, liquid sodium flow inside the tube is cooled, and liquid sodium flow inside the shell is heated.

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