Principles of Chemical Engineering,
Thread Content
The valve is turned down. How do the pressures upstream and downstream change respectively? Simple pipeline
Generally, when the valve is closed, the local resistance coefficient of the valve increases, resulting in a greater pressure loss across the valve. With the pressure before the valve remaining stable, the pressure behind the valve decreases； If it is located at the pump outlet, reducing the size of the pump outlet valve lowers the flow rate through the pipeline, which in turn increases the pressure at the pump outlet. This means that the pressure before the valve increases as well. This situation can be determined by observing the movement of the intersection point between the operating characteristic curve of the centrifugal pump and the pipeline characteristic curve.