A New Water Saving Device of Swirling Flow for Cooling Towers

( SEEand the atmospheric pressure, which could be read directlyfrom the thermohygrograph and the atmospheric pressurePropeller fanTest part、manometer.Test hollParameter measurement inside the towerWater heater Cooling tower50Total pressure and static pressure of the inlet andCorrugated platevelocity of the airflowShower.4030A pitot tube is built in at the extended cylinder forls0592|measuring the total pressure and the static pressure. TheExtendcvlinderhead of the pitot tube is 143 mm away from the cylindercenter and 450 mm above the tower bottom edge level.The pitot is connected to a computer via a micro pressure-90o1060sensor and an A/D board. Assuming that the airflow00is nonviscous and incompressible, its velocity can bePump130Transducercalculated based on the Bernolli equation as follows [1川85SwitchboardPo=p+ρ号(3(30)10(m/s)(1)Rotary flow meterTankElectromagnetic valvep1300Thermometerρ=0.123 kg[.Sm*(2) Fig.4 Sketch of the reduced scale model of water lopcooling tower in laboratoryp=0.114k81:$(3)nwhere P, is the total pressure, p is the static pressure andP, in term of the following:ρ is the dry air density (kg/m). The value of the dry airp=中p,"; p:=p:-p."(6)density is derived from Eq. (2) for the dry air temperaturewhere φ is the relative humidity as φ=p:/p," (0。" is theof 20C and from Eq. (3) for the dry air temperature ofdensity of moist steam ) and it can be witen as φ=p/p,"40C, each under the standard atmospheric pressure.from Eq. 6(p," is the air pressure of moist steam),p。isTotal pressure and static pressure of the outlet andthe atmosphere pressure which can be substituted by thethe temperature, humidity and velocity of the airflowstatic pressure p in the cylinder, and p”can be calculatedAs shown in Fig. 4, a pitot tube is fixed to the testfrom the following Gillie empirical equation (2]; .cylinder through the test hole to measure the totalpressure and the static pressure. The static pressure oflg. p,"=0.0141966 -3.142305T- 373.16the outlet is also measured through four test holes in+8.21g{(273.16 )- -0.0024804(373.16-7) (7)the test cylinder to observe the uniformity. The airflowt)velocity can be calculated from Eq. (1), but the airflow+lg0.0980665density will have to be known. In the experiment, thetemperature and humidity of the airflow are measuredwhere T is the Kelvin temperature (unit: K).by thermohygrograph. Then the airflow density ρ can beobtained from the following state equation.The airflow velocity in the test cylinder can beρ=Pa+p,(4)calculated from Eqs. (5), (6) and (7), and the airflowwhere Pa is the dry air density and P。is the humid airvelocity at the water saving devices can be calculatedbased on the conservation of mass.density, respectively.ThereforeP=RI+RT(5)The airflow velocity is also measured at the top of thetank by using vane anemometer.where Rj -297.14 m2/s.K is the gas constant of dry air,Water ten中国煤化工the outletR= 461.53 m?/s3-K is the gas constant of steam, P。is theAs shownDle thermometerdry air pressure and P, is the steam pressure，withp, and is fixed at tiTYHCNMHGtomeasurethe54.ELECTRICITY 2011.4，.