Experimental Study On Daub-type Surface Evaporative Cooler

Evaporative cooling is widely used in air conditioning systems, such as air water spray chamber and cooling towers. When using the cooling tower, there are some problems, such as noise pollution, the installation area and so on, these issues were prominent in some specific situations, such as the subway station air-conditioning system. In order to search for a new and reasonable method of heat extraction at the terminal of Metro Air-conditioning system, and making full use of ventilating channels space and ventilation system, this article proposes a new way of evaporative cooling to cool the Air-conditioner system cooling water—the smear surface-evaporative cooling, which is said that in order to keep outside surface of the heat-interchanger in a wetted condition and do not have a water film with large thickness flowing, during the same time when spray water on the outside surface using a rotating smear-device to smear it, then the evaporation of water on outside surface of the heat-interchanger taking away heat from the heat-interchange internal cooling water. This study carried out some experiments on the evaporative cooler way.By comparing various types of heat exchangers, designed for evaporative cooling rotary heat exchanger painting - double helix coil heat exchanger. Water requirements of coated-type fabric with a compact heat exchanger, flat heat transfer surface in order to smear the entire heat transfer surface water distribution, and as much as possible reduce the applicator size and resistance. Double helix coil heat exchanger can be a good fit for smear-style cloth in water, while the bearing capacity and good heat transfer performance. Double helix coil heat exchanger with two parallel brass circle made by spot welding between pipe fixed centers of the coil connected with a U-shaped connector, the heat exchanger made from two parts of the forward, return spiral.Designed coated water distributor to meet the test requirements of. Apply water distributor device and applied by the replenishment brush composed of the former painting brush and heat transfer through the contact point parts of additional evaporation of water spray, which spray water in the heat exchanger so that the surface of film. A requirement replenishment of small amount of water evenly, and apply the brush requires a hydrophilic, abrasion resistance and flexibility, and can be completed thoroughly coated coil gap. Spread through the water distributor of a variety of experimental contrast, and ultimately determine the use of water + nozzle and fill bristle brush smear combined water distributor.Analysis of the coated surface evaporative cooler type heat and mass transfer process and the evaporation of water covered the outer surface of the formation mechanism. Heat convection cooling water passes through the wall, and then coating the outer surface of the way through the heat absorbs heat from the wall, and finally through evaporation in the form of latent heat into the air. The closed cooling tower heat transfer process with the largest difference between its evaporation processes directly on the heat exchanger surface. Film is mainly applied water distributor through the mechanical action of the formation; it is sufficient to maintain the outer surface of moist heat exchanger and has a massive distribution of particular local water film, the distribution of the main factors affecting the surface tension of water and hydrophilic outer surface of heat exchanger performance.Built the bench of Low-speed wind tunnel, the entire bench from the wind tunnel, cooling water system and apply the water system. Wind tunnel used to regulate air flow rate and installation of a fixed heat exchanger, the air duct and fan components; cooling water system for the experiment to provide hot water around 37℃, the water supply system and temperature control system components; applied for the complete water system Apply the heat exchanger surface of the water distribution services, to achieve the periodic heat exchanger surface water distribution to form a uniform continuous film, and makes the evaporation process directly on the heat exchanger surface, the hollow shaft, rotary pay connector, replenishment tube and gear, and other major components.Finally, the use of low-speed wind tunnel test system for experimental study of evaporative cooling on the surface of smear-type heat exchangers properties and influence. Mainly on the outer sweep of air temperature, humidity and speed of the cooling water flow and temperature speed and spread of water and the heat exchanger tube diameter and length on the heat transfer performance.