Encyclopaedia Index

### TITLE : Lid-driven flow in a radiating cavity

BY : Dr S V Zhubrin, CHAM Ltd

DATE : October, 2000

FOR : Demonstration case for V3.3.3.

### INTRODUCTION

An IMMERSOL application is presented aimed at the demonstration
of the method for the situation when both thermal radiation and
convection affect the heat transfer.

### THE STATEMENT OF THE PROBLEM

This simulation analyses the flow in a chamber, the floor of which
moves with a constant velocity, 1m/s. The stationary walls are adiabatic,
the moving wall is at a 300K.

A radiant heater panel is placed at the top of the chamber. It consists of
a row of cylindrical electrical heating
elements 1 cm in diameter, 150 cm long, spaced at a 3 cm pitch, and backed
by a well insulated wall. The panel has dimensions 30x150 cm and is
located 30 cm above a workpiece floor, which is also 30x150 cm. The heater
elements are rated at 5 kW each. The emittances of the elements and back
wall are 0.9 and 0.8, respectively; the workpiece floor is
assumed black at 300K. The black side walls are supposed to be made from refractory
(adiabatic) bricks.

The task is to calculate the operating temperatures of the heater elements,
side wall temperatures from the velocity and temperature fields and radiative
heat fluxes distributions.

### COMPUTATIONAL DETAILS

### Conservation equations

The independent variables of the problem are the two components of
cartesian coordinate system, namely X and Y.

The main dependent (solved for) variables are:

- Pressure, P1
- Velocity components, U1 and V1
- Temperature of the medium, TEM1 and
- Radiative temperature T3.

### Model of radiative transfer

The IMMERSOL model is used to simulate the distribution of T3 and TEM1
within the space filled with transparent air. From the temperature fields
the radiant heat fluxes, QRX and QRY, W/m^2, are calculated and used as
the heat sources in iterative manner.

### Properties and auxiliary relations

The gas density is taken constant as for air at 20C with
no absorption and scattering. The kinematic viscosity depends on
the temperature as Sutherland relationship dictates.

### THE RESULTS

The plots show the distribution of the velocity vectors, temperature and
X-, Y-direction radiant heat fluxes within the enclosure.

Pictures are as follows :

### THE IMPLEMENTATION

All model settings have been made in VR-Editor of PHOENICS 3.3.1.

The relevant Q1 file can be inspected
by clicking here.