Experimental Approach to Assess Evaporative Cooling Under Forced Air Flow

Abstract

Air blast is one of the most employed industrial chilling methods. It can be enhanced, i.e., increasing heat transfer and reducing cooling time, by superficial evaporative phenomena. This work reports a methodology, including experimental setup and mathematical modelling, to quantify the air chilling enhancement by wetting the surface of the object to be chilled. A spherical metal model was covered by a cotton tissue (wet or dry) and placed into a cold chamber. The effective heat transfer coefficient was determined at different temperature, air velocity, and relative humidity from time-temperature profiles into the sphere. Under the same air conditions, the effective coefficient between sphere and air was increased threefold by moistening the cotton tissue on the sphere surface. Furthermore, comparing a dry and wet surface showed that evaporative cooling resulted in much shorter chilling times. The proposed approach was able to assess evaporative heat transfer by measuring only the time-temperature profile, and is suitable for industrial applications.

Experimental investigation of air cooler using local palm tree waste

“…The cooling effectiveness increases with an increase in air velocity and a decrease in water temperature. The effect of airflow velocity and water flow rate on the performance of direct and indirective evaporative cooling systems is also conducted by Franco et al [14], Rodrigues et al [17], and Antonellis et al [18]. Overall it is noted that the performance is significantly affected by the water flow rate.…”

Effect of Steel Plate Thicknesses and Fluid Flow Characteristics of an Impinging Air Jet on Heat Transfer at the Stagnation Point

“…The uncertainty of the effective thermal conductivity was ± 20%, while the uncertainty in measuring the flow velocity or Reynolds number was 1 to 2% (Kline and McClintock, 1953;Kim et al, 1993;Mahgoub, 2013). Evaporative cooling using air flow was also investigated (Rodrigues et al, 2017).…”