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EastWindBreaks
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Homework Statement
Hot and cold streams of a fluid are mixed in a rigid mixing chamber. The hot fluid flows into the chamber at a mass flow rate of 5 kg/s with an energy in the amount of 150 kJ/kg. The cold fluid flows into the chamber with a mass flow rate of 15 kg/s and carries energy in the amount of 50 kJ/kg. There is heat transfer to the surroundings from the mixing chamber in the amount of 5.5 kW. The mixing chamber operates in a steady-flow manner and does not gain or lose energy or mass with time. Determine the energy carried from the mixing chamber by the fluid mixture per unit mass of fluid, in kJ/kg.
Homework Equations
energy balance equation for open system
The Attempt at a Solution
I already have seen the solution but since the problem did not specify the existence of an outlet. I am confused about if there is an outlet from this chamber or not, if it has only 2 inlets, then the mass flow rate of the mixture still equals the sum of the inlets mass flow rate, correct? and the mass flow rate of the mixture is just the mass rise rate of the mixture in the tank right? since the mixture has no outlet to flow into, it can only rises. but without an outlet, the change in kinetic energy would not be negligible anymore right? since the fluid velocity in a tank is negligible compare to the velocity inside the pipe. but to find the velocity of the inlets, we need the inlets areas which are not given, so do we always assume that a mixing chamber problem has an outlet?
