Question 18 on professional knowledge in the morning of 2013: What is the change in pressure drop?
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For a rotameter, when the water flow rate is 1 m3/h, the pressure drop across its inlet and outlet is 20 Pa. Why is the corresponding pressure difference still 20 Pa when the flow rate increases to 1.5 m3/h? Since the flow rate is higher, the flow velocity should also be 1.5 times higher; therefore, the pressure drop should be 45 Pa, right? Could an expert answer this?
Features of rotary flow meters: variable cross-section with constant pressure difference; as the flow rate increases, the flow area above the rotor increases to maintain a constant pressure difference