2.4 Mist generation system performance
The measurements performed at a given height. The different height of the liquid above the ultrasonic transducer was adjusted to 1, 2, 3, 4, 5, 6, and 7 cm ± 0.1. The mist was decelerated by gravity effect, the mist particles would come to a stop in only 2 mm over the liquid surface (Barreras et al., 2002). This dense fog should be transmitted by the air force for further application. The inlet airflow rate was set at 25 lit/min at a pressure of 2 bar when it was required. During the misting mode of operation, the total lost weight of medium, Mist total, occurred by airflow (surface evaporation, Mist air ) and ultrasonic effect (Mist US ). In order to evaluate the performance of the misting system and determine the contribution of ultrasonic transducer (Mist US ) accurately, at first the surface evaporation of medium was determined (Mistair ). To obtain Mist air , the air was blown on the quiescent medium when the ultrasonic transducer was turned off. The exhaust gas momentum and its heat transfer lead to accelerating the surface evaporation of the solution in the mist chamber and caused weight loss that was due to surface evaporation. The slope on mass-time variations was presented as mass flow loses caused by surface evaporation (equation 4). To ensure to have a stable condition of the weight loss, the middle three-minute period of the weight loss-time chart was considered (Fig. 2). The value of MistUS determined indirectly by knowing the Misttotal and Mist air , then the Mist US was obtained by equation 5. To obtain the Mist total and Mist air , the system only was run for 6 minutes at a given height of 1, 2, 3, 4, 5, 6, or 7 cm.