INVESTIGATION OF HEAT TRANSFER FROM SATURATED MOIST AIR TO THE VERTICAL WALL OF A HEAT EXCHANGER WITH WATER VAPOR CONDENSATION

Abstract

The relevance of the study is determined by the need to apply a universal method of design calculation for deep heat recovery installations in ventilation systems or flue gas removal systems. The use of heat recovery units significantly increases the boiler efficiency. The most problematic task is the calculation of the heat transfer coefficient from the vapor-gas mixture to the heat exchange surface during the condensation of water vapor. Conducting experimental studies of this process is necessary to improve the calculation methods in various ranges of canges in the gas-vapor mixture parameters. The purpose of this research is to obtain a criterion similarity equation for calculating the heat transfer coefficient from the vapor-gas mixture to the heat exchange surface during condensation of water vapor in a certain range of mixture parameters. Objects: surface-type heat exchanger (condenser), vapor-gas mixture, steam generator. Methods: energy balance, design calculation of the heat exchanger, thermodynamics, heat transfer, similarity method, dimensional analysis method, heat transfer experiments, error analysis. Results. Experimental studies of the heat transfer process during the water vapor condensation from a gas mixture were carried out on a laboratory installation. The results were processed with an estimate of the measurement and calculation errors. On the basis of the similarity theory, a criterion equation is obtained for calculating the heat transfer coefficient from the vapor-air mixture to the heat exchange surface in a certain range of the criteria variation. The deviation of the calculated heat transfer coefficients and those obtained experimentally did not exceed 13 % for different directions of the vapor-gas mixture flow. The criterion equation can be used in the design of heat exchangers for heat recovery.

Keywords

• condenser
• heat recovery
• gas-vapor mixture
• criterion equation
• heat transfer coefficient
• vapor condensation