In this paper the flow past a 2" sized globe valve is numerically simulated and the valve sizing coefficient (C_V) is calculated using CFD. A theoretical study using elementary techniques is exercised to understand the significance of the flow coefficient (C_V) in predicting the mass flow rate through the valve. This exercise gives way to a clear understanding of the inherent simplicity of the function of a valve. A commercial grid generation tool ICEM-FLUENT is used for mesh generation. Commercial fluid dynamics code, ANSYS FLUENT is used for the flow modeling. For the static analysis, fully opened valve position is used and 1 atm through 7 atm of pressure difference (ΔP) is applied across the valve numerically. The numerical data obtained from the simulations is then used to calculate the flow coefficient (C_V) computationally. From the results obtained it is found that the flow coefficient was indeed a constant for the same set of pressure differential and mass flow rate. The flow coefficient value is thus proved to be a function of the valve structure. By comparing between numerical and experimental results it is concluded that flow coefficient (C_V) can be predicted with agreeable accuracy using computational techniques.