In order to understand the mechanism of ash deposition on the surfaces of heat exchanger tubes in lignite utility boilers, a numerical computer code for the prediction of the fou1ing process will be further developed. Its reliability will be tested against experimental and industrial data.
A computer model simulating the fouling mechanism for a two-dimensional particle laden gas flow was developed in a past contract (EN3F-0022). In the previous contract, a Lagrangian particle tracking method was developed using Eu1erian time and length scales. This model will be improved and extended to curvilinear orthogonal coordinates so as to investigate fouling mechanisms in complex heat exchanger geometries. The code will solve numerically NavierStokes equations on an orthogonal body fitted coordinate system; the Lagrangian particle tracking method will employ Lagrangian time and length scales. A conditional sampling method will be employed for particle tracking.
Experiments will be used to test the reliability of the numerical code. Typical tube arrangements found in utility boiler heat exchangers will be assembled and the flow field will be examined in detail using laser velocimetry techniques. Measurements will be performed by means of image processing techniques.
The Greek Public Power Corporation will identify important parameters of fouling and superheater arrangements. They will also carry out industrial tests for ash build up on the tubes.
Funding SchemeCSC - Cost-sharing contracts
WC2R 2LS London