Hammer Transient Analysis : TCV and FCV

To add to Scott's reply: if you use a FCV to limit the flow and you set "modulate valve during transient" to "False", then it will remain in a fixed position based on the initial conditions. If you want to account for the reaction time and throttling of the valve during the transient simulation to meet the flow setpoint, set it to "true" and enter the appropriate coefficients to simulate the reaction times per the article Scott mentioned.

However, if there is not actually a flow control valve that throttles to control the flow in the real system, see this article and instead you may need to consider this a calibration exercise, or adjust the demands to match the observed outflow.

Note also that demands are treated as pressure dependent during a transient simulation in HAMMER (see this). Meaning, the demand will drop as the pressure drops.

To add to Scott's reply: if you use a FCV to limit the flow and you set "modulate valve during transient" to "False", then it will remain in a fixed position based on the initial conditions. If you want to account for the reaction time and throttling of the valve during the transient simulation to meet the flow setpoint, set it to "true" and enter the appropriate coefficients to simulate the reaction times per the article Scott mentioned.

However, if there is not actually a flow control valve that throttles to control the flow in the real system, see this article and instead you may need to consider this a calibration exercise, or adjust the demands to match the observed outflow.

Note also that demands are treated as pressure dependent during a transient simulation in HAMMER (see this). Meaning, the demand will drop as the pressure drops.