![density of water in lbmft3 density of water in lbmft3](https://littlebinsforlittlehands.com/wp-content/uploads/2015/01/Rainbow-Sugar-Water-Density-Tower-test-tube-science-activity.jpg)
while the outlet flow through the pump is 9200 lbm/sec. The continuity equation can also be used to show that a decrease in pipe diameter will cause an increase in flow velocity.Įxample: Continuity Equation - Centrifugal Pump The inlet diameter of the reactor coolant pump shown in Figure 3 is 28 in. So by using the continuity equation, we find that the increase in pipe diameter from 6 to 8 inches caused a decrease in flow velocity from 22.4 to 12.6 ft/sec. Letting the subscript 1 represent the 6 in. section must equal the mass flow rate in the 8 in. section?įrom the continuity equation we know that the mass flow rate in the 6 in. section, what is the flow velocity in the 8 in.
![density of water in lbmft3 density of water in lbmft3](https://image2.slideserve.com/3737941/slide4-l.jpg)
![density of water in lbmft3 density of water in lbmft3](https://d2vlcm61l7u1fs.cloudfront.net/media/6e4/6e472c6b-d0eb-47e4-8201-42c484cddb84/phpkEGEY8.png)
If the flow velocity is 22.4 ft/sec in the 6 in. The density of the fluid in the pipe is constant at 60.8 lbm/ft3. Steady-state flow exists in a pipe that undergoes a gradual expansion from a diameter of 6 in. One of the simplest applications of the continuity equation is determining the change in fluid velocity due to an expansion or contraction in the diameter of a pipe.Įxample: Continuity Equation - Piping Expansion The continuity equation for this more general situation is expressed by Equation 3-6. The continuity equation for this situation is expressed by Equation 3-5.įor a control volume with multiple inlets and outlets, the principle of conservation of mass requires that the sum of the mass flow rates into the control volume equal the sum of the mass flow rates out of the control volume. For a control volume that has a single inlet and a single outlet, the principle of conservation of mass states that, for steady-state flow, the mass flow rate into the volume must equal the mass flow rate out. The continuity equation is simply a mathematical expression of the principle of conservation of mass.