Heat Transfer Enhancement of Square-Pitch Shell-and-Tube Spray Evaporator Using Interior Spray Nozzles

This study proposes a new nozzle/heater arrangement for enhancing the heat transfer coefficient of a square-pitch shell-and-tube spray evaporator. In the proposed approach, the nozzle tubes are positioned within the tube bundle in such a way that the surface of each heater tube is sprayed simultaneously by four cooling sprays. As a result, the dry-out phenomenon on the lower surface of the heater tubes is prevented. The experimental results reveal that the shell-side heat transfer coefficient obtained using the proposed spray technique is significantly higher than that achieved in a conventional flooded-type evaporator. Moreover, it is shown that the heat transfer performance increases as the saturation temperature decreases and the spray film flow rate increases.