What are the key considerations in control valve sizing?

Key considerations: calculate Cv at normal, minimum, and maximum flows (valve must handle full range), check for cavitation/flashing using pressure recovery factor (Fl), verify velocity limits for noise and erosion, select trim style for required characteristic, ensure adequate pressure drop at control valve (25-50% of system dP for good control), and check rangeability (ratio of max to min controllable flow, typically 30:1 to 50:1 required). Oversizing causes poor resolution; undersizing limits capacity. Use manufacturer software for accurate sizing.