The discharge coefficient Cd is defined as actual over theoretical discharge (equal to Cc × Cv). For a typical orifice, Cd is approximately__________________?
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Answer: B. 0.62
Explanation
Standard orifice meters operating under typical turbulent conditions exhibit a discharge coefficient of approximately zero point six two. Contraction and velocity coefficient product for standard orifice plates yields this empirical discharge value. Experimental calibration curves confirm discharge coefficient values hover near zero point six two for turbulent flow. Discharge coefficient accounts for energy losses and jet contraction downstream of an orifice plate. Orifice meter calculations require accurate discharge coefficients to determine actual mass flow rates. Pipe Reynolds number and tap location configurations cause minor variations around the zero point six two value.
Process control engineers program flow computers using zero point six two as a standard orifice coefficient. Natural gas metering stations calibrate orifice assemblies to ensure custody transfer measurement accuracy. Water treatment plants install standard orifice meters to monitor chemical additive dosing flow rates. Option A lists zero point four two, which underestimates standard orifice discharge coefficients. Option C lists zero point eight two, which overestimates typical square edged orifice plate coefficients. Option D lists zero point nine eight, which represents venturimeter coefficients rather than orifice plates.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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