【Daily Question No. 26】March 26, 2018
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A Explanation: When the diameters are the same, flow from a nozzle is significantly faster than that from a orifice. Therefore, to achieve the same flow rate with a nozzle and an orifice, the diameter of the orifice must be made larger than that of the nozzle. Key examination points: free outlet flow, submerged outlet flow, nozzle flow. Summary of Daily Questions for Registered Electrical Engineers in 2018
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Under normal operating conditions, if the diameter of the thin-walled orifice is d1 and the diameter of the cylindrical nozzle is d2, and the head of water acting on them is equal, then for the flow rates through the orifice and the nozzle to be equal, the relationship between the diameters d1 and d2 is (A). The formulas for the flow rates through both the thin-walled orifice and the cylindrical nozzle are: http://admintk.100xue*.com/UpLoadImage/2013-05-07/cac5e427-073d-48e3-97f1-62b8e473c539.jpg. Area: http://admintk.100xue*.com/UpLoadImage/2013-05-07/28f8830e-6d90-4cb5-9361-abfe3a991bb5.jpg. Based on the given conditions, Q1=Q2 and H01=H02. By substituting the address http://admintk.100xue*.com/UpLoadImage/2013-05-07/500ae996-ce1a-4baf-a39f-aea475a2d91e.jpg, we get: http://admintk.100xue*.com/UpLoadImage/2013-05-07/0f358512-08ec-41cd-9a39-04ac8ea95dc9.jpg. Also, since the flow coefficient μ2 > μ1 (0.82 > 0.62), d1 > d2.