Heat-mass transfer model and irreversible heat transfer process analysis of high-humidity exhaust

In engineering, the efficient extraction of low-grade energy from mine exhaust is a key issue. Based on the heat-mass transfer between high-humidity exhaust and low-temperature spray in the heat recovery diffuser tower, a theoretical model of heat-mass transfer about the number of mass transfer units (NTUm) and Lewis number (Le) is constructed and solved, the direct contact heat-mass transfer test is carried out. Applying the entransy dissipation theory, the irreversible process of heat-mass transfer is clarified, and the relationship between Le and the thermal resistance of entransy dissipation is revealed. The results shows that the heat-mass transfer process between high-humidity exhaust and low-temperature spray is embodied as two processes, which are dehumidification cooling and quasi-isohumidity cooling. When NTUm is greater than 0.1, the high-humidity exhaust is dehumidification cooled. After heat exchange with low-temperature spray, the air temperature can be reduced by up to 6.3 ℃ and the moisture co