I am developing a regression model to predict the mass flow rate of a Direct Expansion Solar Assited CO2 heat pump (for a needle valve expansion device). The mass flow is based on the following equation:
m = Cd * A * [2 * rho * (Pi-Po)] ^ 0.5
For tests done in the sun, we have found a cd greater than 1. I expected this correction factor to be less than 1. But my experimental data, apparently show the opposite.
You need to check the units of terms carefully and how each value is measured. If Cd is greater than once, it means that leakage or loss is taking into the flow system. So you have check the design carefully if any fluid is getting into the system.
Hello . In practice, the discharge coefficient cannot be greater than one. This is a fact. The error may be in compensating the values of the variables in the equation. Verifies units, values, and homogeneity of area values.
I think,there are mistak with uint of this equation.please check the units for all parameters within this equation.
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