The phenomena of fouling can significantly deteriorate the intensity of heat transfer process and influence heat exchanger performance. The correct account for fouling is especially important in PHE with much higher heat transfer coefficients than in tubular heat exchangers. The mathematical model of heat transfer in PHE subjected to fouling is proposed. The model is represented by the system of partial differential equations which integration permit to estimate local parameters of heat exchanging streams and developing in time local values of fouling depositions layer thickness. The fouling rate is determined with the use of fouling deposition model proposed earlier. The model is validated by comparison with the data obtained for PHE working in industry and can be used for more accurate calculation of PHE heat transfer area in conditions of fouling formation than methods relying on averaged process characteristics. The model application is illustrated by two case studies for PHE application in sugar industry and in District Heating system.
