Experimental Characterization of Liquid Flows in Cooling Tower Packing

Abstract

Wet cooling towers are used in many industrial processes. Although the heat transfer phenomena have been well studied in this kind of towers, the hydrodynamic behavior of air− water counter flows in industrial cooling tower packings remains unknown and has never been studied with local experimental approaches. Hydrodynamics are directly linked with operating issues such as packing fouling reducing cooling efficiency, or circuit operating optimization conditions that have an impact on the industrial plants' performances. The objective of this work is to develop representative tools to understand and characterize liquid/ air flow inside industrial cooling tower packings. In order to study the hydrodynamic characteristics of liquid/gas flows in a widely deployed industrial packing, a pilot-scale experimental cooling tower has been designed, built, and operated. The experiments allowed the visualization of a falling water film along the packing sheets. Specific methods have been developed to measure main flow parameters such as the water film thickness and the packing wetting rate depending on the operating air and water conditions. The contrast method allows the measurement of water film thickness with time around several hundreds of micrometers with a precision below 10 μm. The fluorescence method allows the measurement of the wetting rate on the packing sheets' surface excluding perforations and geometry irregularities. These observations highlighted the strong instability of falling water films. The statistical distributions showed a mean water film thickness between 300 and 600 μm. Under industrial operating conditions, the wetting rate is far below 100%, and it increases when the water flow inlet increases; meanwhile, the thickness is not significantly affected for nontotal wetting.

Recent Progress in Fill Media Technology for Wet Cooling Towers

“…Jourdan et al [12] Material: PVC Specifications: It is composed of various thermoformed PVC sheets of 0.06 cm thickness and forms a sinusoidal pattern with a period of 5 cm and an amplitude of 1.7 cm.…”

Compartmental Modeling of Biofouling in Industrial Cooling Circuits

“…The experiments allowed the visualization and measurement of a falling water film along the packing sheets. Specific methods have been developed to measure main flow parameters such as the water film thickness and the packing wetting rate depending on the operating conditions [12]. In addition, CFD simulations were performed to obtain complementary data about liquid flow in cooling tower packing [13].…”

Analysis of the Effect of Packing Materials (Fills) and Flow Rate on the Range and Efficiency of a Forced Draft Evaporative Cooling Tower

“…Kariem [16] analyzed the counterflow WCT using high-density polyethylene fills and concluded that the cooling tower performed its best at the lowest L/G ratio. Jourdan [17] visualized the water film thickness of the falling water on the fills, and the wetting rate of the fills were studied. They observed the mean water film thickness in the range of 300-600 µm.…”