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monet man
Oct29-11, 02:21 PM
Hello all. I am new to this forum. I am an electrical engineer, and I am working on a system which requires me to calculate a flow rate. Once I know this, I can continue with the design. Since I am an electrical engineer, I have insufficient knowledge of fluid dynamics to know how to set up the necessary equation(s) to compute the needed information. That being stated, I will tell all that I can about the system variables, and hopefully if I have given enough info, I will get some assistance in setting up the equation.

I have a cubic (6-sided) liquid reservoir which will contain hydrochloric acid (30% ~ density 1149 kg/m^3).

The bottom side of this reservoir has a 1" (2.54cm) hose that is used to drain this tank.

The hose is connected to a valve with a sharp-edged opening (orifice coefficient,Co, I assume is 1 (?)) which measures 3/8" (0.9525cm) in diameter.

I need to calculate the time that it will take the tank to drain. For calculation purposes, say that the tank is 1m x 1m x 1m, and the tank is full (height of HCl = 1m).

I feel that the height must be a variable for integration (i.e. dV/dy)...but I also want to know the height of HCl in the tank at any given time (i.e. dV/dt). I have been looking online for the answers all day, but my head is starting to hurt from all of the information that I am finding, and I think that I am making this way too complicated for myself. Any help is GREATLY appreciated.

Highway
Oct29-11, 05:41 PM
Bernoulli's: http://www.efunda.com/formulae/fluids/draining_tank.cfm

Did you run into this while googling?

BadBrain
Oct29-11, 07:16 PM
monet man:

Try figuring Bernouli's Equation for youself.

See:

http://www.engineeringtoolbox.com/bernouilli-equation-d_183.html

gsal
Oct31-11, 08:03 AM
This matter has also been discussed a few times in this forum...here is one thread (http://physicsforums.com/showthread.php?t=507578)