Hydrodynamic tests of regular packing for implementing evaporative cooling process

Abstract

In this article, a description is given of hydrodynamic test data for a new short-layered regular packing from corrugated polymer sheets for evaporative cooling of circulation water in cooling towers. The test data are depicted as dependence of hydraulic resistance coefficients on airflow velocity.In order to raise the efficiency of evaporative cooling in cooling towers, use is made of packing devices with a developed contact surface. A great many packing designs have been proposed for intensifying evaporative cooling in cooling towers. The most popular ones are structured packings belonging to the family of film-type packing devices [1]. These packings are made in the form of blocks of various heights from corrugated sheets [2][3][4][5][6]. In spite of their high heat-and mass-transferring efficiency, structured packings have a number of deficiencies, one of which is uneven distribution of phases over the apparatus cross section because the geometric structure of these packings prevents communication of the contacting flows between the channels formed by the adjoining sheets [7].One of the promising lines of improving film-type regular packings is use of "end effects" [8]. Using end effects, the Moscow State University of Engineering Ecology (MGUIE) has developed a short-layered packing (SLP).In this work, studies have been made of the heat-and mass-transfer and hydrodynamic characteristics of the new film-type regular packing. The new packing ensures intensification of cooling of circulation water on account of gaps between the tiers (rows) and turning of the adjoining tiers by 90°relative to each other, i.e., on account of use of end effects. The gaps created between the tiers by using spacers facilitate breakup (disruption) of the liquid film, agitation of the flow, and increase in transverse motion of the contacting flows. According to the data in [2,9], these methods help accelerate heat-and masstransfer processes.This article contains hydraulic resistance test data for blocks of a newly designed dry and irrigated (sprinkled) SLP of various heights. The SLP was built around the 19-type packing made by the company CHV [6]. The new design was created from the elements of this packing. The general view of the original packing block is shown in Fig. 1.The blocks of the tested SLP were assembled from vertically arranged corrugated (crimped) polypropylene sheets contacted by projecting trapezoid corrugations. The corrugations on the adjoining sheets were slanted on opposite sides with a 60°angle to the horizontal plane (floor). The height of the crest of the trapezoid corrugations was 19 mm. Each sheet was 0.44 mm thick [6]. The total height of the SLP blocks was 0.96, 1.05, and 1.23 m. The block of the new packing consists of tiers so arranged that each successive tier is turned 90°in the horizontal plane relative to the preceding one. The adjoining tiers were separated across the height by spacers. Consequently, the block with a height of 0.96 m consisted of three tiers of 0.3 m in height each and two gaps of 0...

Analysis of Heat and Mass Transfer Characteristics of Distillation Column with Structured Packings with Different Geometrical Parameters

“…However, because of the complexity of the interaction of vapor and liquid in the channels of packing, which have a very complex geometrical structure, the processes of heat and mass transfer do not allow rigorous mathematical description so far. Experimental data on the heat and mass transfer and pressure drop in columns with structured packings are very scarcy [1][2][3][4][5][6][7][8][9][10][11][12][13].…”