Heat and Mass Transfer in Open Evaporative Cooling System Using Various Types of Fills In Oil Industry

Abstract

 This research work is to study the performance of evaporative cooling system using new type of packing with different shapes (saddle, counter current wavy, and  triangular splash) and materials (glass, thermoplastic, and resistance wood) of  packing for an air –water cooling system . The basis of the installation is the evaporative cooling system,1.75 m height and 40 x 40 cm outside cross section. The fluids in this system are air which moving from the bottom to the top of cooling system (mass flow rates ranging between 0.07 and 0.18 kg/s) and the water which are moving from top to bottom of cooling evaporator ((mass flow rates ranging between 0.11 and 0.27kg/s)). The inlet water temperatures ranging

between 35 and 55^oC .The packing heights  were changed during the research in order to get the temperature profile and the relation of these temperatures with the other variables in the cooling system, the packing heights ranging between 35 to 140 cm. The overall volumetric heat and mass transfer coefficients and tower characteristics, were predicted as a function of the fluids flow rates.

A computer program used to solve and find the relation between the variables in the system and the functions (overall volumetric heat and mass transfer coefficients, number of transfer coefficient, the temperature variation along the tower).

The results show that :

 1-At maximum air mass flow and

    minimum water mass flow, the

    mass transfer coefficients would

    be on the maximum value and

    vice-versa.

2- The thermoplastic packing was

    much more efficient than glass

    and wood by efficiency about 12

    to 18 %. ,also the results showed

    that The triangular packing was

    much more efficient than wavy

   and  glass by efficiency about 5 to

    11  %.

3-The temperatures distribution

were not constant in all layers; the temperatures distribution in the first layer were not very well, this happened because the distribution of water in the packing surface was just  know happened, while in the other layers the temperature distrib-ution and profile were so good.