Numerical study of the cooling capacity and pressure drop in a hybrid closed circuit cooling tower

Abstract

Numerical jnvel-ligation 011 the i-Iybrid CloscJ Circuit Coolin!; Tower (HCCCT) having a rated capacity of 2RT has becn done inlhis 5ludy. Here now characlcrislics h~ve been analY7,cd using gCllcrailzc(1 ~lOn-Oithogonal coonJinalc sY5lcm ~, (he problem demanded. The internal flow liclds have been studied by solving the laminar type viscous model and tho problem related to pressure vcluel!y coupling was hundled using the SClllilmplicit Melhod for Pressure Linkcll Equation, (Sl.l\1PLE) algorilhm. In a HeceT, procc~s fluid remains completely isolated from the ambient air, sa (he quality orlhe process fllnd is protected, and ail'bome contaminants are prevented from entering and fouling the system. HCCCT can provide clean process fluid to the ;ystel1l and reduces system maintenance costs and water treatment costs for evaporative equipment. Dry mode operation ean eonser"e water and treatment chemicals, prevent icing, plume and allow variable speed pumping, thereby conserve energy. The performance ciwraeteflStics of the HCCCT wcre lllllllerieally investigated using nominal (}pefJ.ting condition. The heat transfer pipe used in this simulation is a bare-type wpper coil having an outer diameter of lomm. Tile pressure drop and cooling capacity were studied having air Inlet located both at side wall and at the bOltOlll end for different transverse pitches for various vcloclhes, The numerical simulalion demonstrate<! that when air is supplied from the sHle wall of the HCCCT, the prcsslIl"edrop can bc over estimated and the cooling capacity of tile tower call be under cstilll;ltcd mainly due to non_uniform air now dislribution across the coil bank. The result obtained Ii'om tillS study is s~pposed to provide basic data which could be referred for the optimum design of the hybrid closed circuit cooling towers.