An Experimental Study On Water Distribution Uniformity Of Micro Pressurized Water Distribution Device With Evaporative Cooling Pads

This thesis analyzes water distribution uniformity of micro pressurized water distribution device with evaporative cooling fillers from the perspective of theory, and then carries out a series of experiments to proof results from above theory. Both theoretical analysis and experimental tests on water distribution uniformity are examined from two aspects: a) water outlets of water distribution pipes; b) shunts homogeneity of water dispersal devices. Theoretically, it’s not practical to ensure an absolutely uniform distribution for water pipes with equivalent pipe diameter, equivalent hole diameter and equidistant distributive holes, which are common in engineering practice. However, since we identify the vital factor to water uniformity distribution, we can get to a qualified uniform distribution in practical engineering by adjusting the pipe open porosity. Water dispersal devices are shunts in essence. We suppose the device have specified number of water tanks guiding water diversion. After an hydraulics analysis on water tanks, we can deduct discharge coefficient m, which indicates its internal factors and determines water flume. Through the above theoretical analysis, the water dispersal uniformity is achievable via the flow control in each water tank, which results from a consistency in the size, shape, material and processing technics.The test rig is set up to testify the above conclusion from theoretical deduction. First, testings on the single-hole flow of water distributor and of water distribution pipe are carried out separately as baselines for contrast and comparison, from which we understand their defects. The device can only meet the basic requirements of water distribution uniformity, but its water flow distributed has obvious fluctuation. In theoretical analysis on the outflow of its water distribution pipe, the water distribution uniformity, the ratio of minimum water flow to maximum flow, can get to 0.99. While data got from the testing is 0.85. The experimental and theoretical deviation is 14%, which mainly results from experiment devices. Then, experiments of improvements devices are conducted one by one to test the water dispersal performance. The optimizing testing finds out water dispersal device with internal groove tanks on cover has the best performance, which is consistent with ideal device in the theoretical hypothesis. The variance of recorded data from each test point along the above water dispersal device is 0.012, while that of the baseline is 0.023. The uniformity coefficient of water distribution C_u ranges from 0.8 to 0.9. However, only an eight percentage(8%) of C_u scatters in the range 0.8-0.9. Instead, about 40% spreads in the range 0.6-0.7 and 0.7-0.8. Therefore, the water dispersal device with internal groove tanks on cover can effectively improve the uniformity of water distribution.