Thermal performances investigation of a wet cooling tower M. Lemouari a , M. Boumaza b, * , I.M. Mujtaba c a Department of Processes Engineering, Faculty of Sciences and Engineering Sciences, University of Bejaia, Algeria b Department of Chemical Engineering, College of Engineering, King Saud University, P.O. Box 800, Riyadh 11421, Saudi Arabia c School of Engineering, Design and Technology, University of Bradford, Bradford, UK Received 14 February 2006; accepted 29 August 2006 Available online 18 October 2006 Abstract This paper presents an experimental investigation of the thermal performances of a forced draft counter flow wet cooling tower filled with an ‘‘VGA’’ (Vertical Grid Apparatus) type packing. The packing is 0.42 m high and consists of four (04) galvanised sheets having a zigzag form, between which are disposed three (03) metallic vertical grids in parallel with a cross sectional test area of 0.0222 m 2 (0.15 m · 0.148 m). This study investigates the effect of the air and water flow rates on the cooling water range as well as the tower char- acteristic, for different inlet water temperatures. Two operating regimes were observed during the air water contact, a pellicular regime (PR) and a bubble and dispersion regime (BDR). These two regimes can determine the best way to promote the heat transfer. The BDR regime seems to be more efficient than the pellicular regime, as it enables to cool larger water flow rates. The comparison between the obtained results and those found in the literature for other types of packing indicates that this type possesses very interesting thermal performances. Ó 2006 Elsevier Ltd. All rights reserved. Keywords: Wet; Cooling; Tower; Packing; Flow; Thermal; Characteristics 1. Introduction Usually industrial processes produce large quantities of heat which must be permanently removed in order to main- tain standard operating parameters. Cooling towers filled with packing are widely used to dissipate large heat loads from these processes, such as power generation units, chemical and petrochemical plants and refrigeration and air-conditioning systems, to the atmosphere. Their princi- ple is based on heat and mass transfer using direct contact between ambient air and hot water through some types of packing. Indeed, the type of packing used in cooling tower has an important role in the tower as it controls the heat and mass transfer processes between water and air. Several researchers have investigated this subject through experi- mental analysis of the heat and mass transfer processes in these equipments. Simpson and Sherwood [1] studied the performances of forced draft cooling towers with a 1.05 m packing height consisted of wood slats. Kelly and Swenson [2] studied the heat transfer and pressure drop characteristics of splash grid type cooling tower packing. The authors correlated the tower characteristic with the water/air mass flow ratio and mentioned that the factors affecting the value of the tower characteristic were found to be the water-to-air ratio, the packed height, the deck geometry and, to a very small extent, the hot water temperature. They also mentioned that the tower characteristic at a given water-to-air ratio was found to be independent of wet bulb temperature and air loading, within the limits of air loading used in commercial cooling towers. Barile et al. [3] studied the performances of a turbulent bed cooling tower. They [3] correlated the tower characteristic with the water/air mass flow ratio. El-Dessouky [4] studied the thermal and hydraulic per- formances of a three-phase fluidized bed cooling tower. 1359-4311/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.applthermaleng.2006.08.014 * Corresponding author. Tel.: +966 14679151; fax: +966 14678770. E-mail address: boumaza_m@hotmail.com (M. Boumaza). www.elsevier.com/locate/apthermeng Applied Thermal Engineering 27 (2007) 902–909