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Pressure vessel modeling

Pressure vessel modeling

Pressure vessel modeling

(OP)
Hello,

I I need to simulate emergency draining of a steam generator (using Octave). I have a pressurized tank: 3m3in total. Pressure in the vessel is 40 bar(a).Inside the vessel there is 2.2 m3 of saturated water (at 40 bar) and the rest of the volume is filled with steam (also at saturation at 40 bar). The essel is perfectly insulated.

Let's say i open the valve and start draining the boiler at constant rate of 54kg/s. I need to know what is the state of the boiler when I drain all the water. I derived these equations:

(dm/dt) = const.
(dE/dt) = (dm/dt) * e_w(p)
m = m_w + m_e
E = m_w * e_w(p) + m_st * e_st(p)
V_total = v_st(p) * m_st + v_w(p) * m_w


where:

m = total mass in the Steam generator [kg]
E - total enthalpy of the Steam generator [kJ/kg]
dt = time inkrement [s]
m_w = mass of water in the Steam Generator [kg]
m_st = mass of steam in the Steam Generator [kg]
e_w = enthalpy of water in steam generator [kJ/kg]
e_st = enthalpy of steam in the Steam Generator [kJ/kg]
V_total = Volume of boiler [m3]
v_w = specific volume of water in steam generator [m3/kg]
v_st = specific volume of steam in the Steam Generator [m3/kg]


I thus expect the Steam generator to reach phase thermal equilibrium at every point of my time scale.

Is this the best way how to calculate it:? Or am I missing something. Do you have any suggestions how to make my model more realistic with respect to real world scenario????? Maybe I am missin some work that system has to do to push the water through the valve....or not??


Thank you all very much for answers. :)

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