pneumatic chamber
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Hello, I'm creating new pneumatic chamber with inlet and outlet. for such a chamber mass continuity equation would be like this:
mas accumulation rate within chamber = inlet mass flow rate - outlet mass flow rate
as I understand, expression for mass accumulation rate in chamber is the same as in constant volume pneumatic chamber already created in simscape foundation library. I modified the code of constant volume penumatic chamber:
component chamber1
nodes
A = foundation.pneumatic.pneumatic; % A:top
B = foundation.pneumatic.pneumatic; % B:top
end
variables
gas_flow = { 0, 'kg/s' };
heat_flow = { 0, 'J/s' };
pressure = { 0, 'Pa' };
temperature = { 0 , 'K' };
end
parameters
Volume = { 1e-3, 'm^3' }; % Chamber volume
p0 = { 101325, 'Pa' }; % Initial pressure
T0 = { 293.15, 'K' }; % Initial temperature
end
function setup
through( gas_flow, A.G, B.G );
through( heat_flow, A.Q, B.Q);
across( pressure, A.p, B.p );
across( temperature, A.T, B.T );
% Initial conditions
pressure = p0;
temperature = T0;
end
equations
gas_flow == Volume/A.R/temperature * (pressure.der - ...
pressure* temperature.der/temperature);
heat_flow == A.c_v * Volume / A.R * pressure.der;
end
end
it works when I conect pressure source, new chamber, orifice and atmospheric reference, but I have doubts about the results. And it won't work when I connect pneumatic pump made of rotational pneumatic converter (this pump works when I don't use my new chamber). maybe I missunderstood something, and that somebody will help me with this.
P.S. if my question is unclear, please wright to me and i will clarify it.
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采纳的回答
Arnaud Miege
2011-4-8
I don't think it's as simple as this. You need the concept of orifices for the inlet and oulet of the chamber. A better way would be to use the Constant Volume Pneumatic Chamber block from the Foundation Library as a building block for a 2-port pneumatic chamber. A simple way to do this is to use 2 Constant Area Pneumatic Orifice blocks with their B ports connected to the Constant Volume Pneumatic Chamber block.
HTH,
Arnaud
2 个评论
Arnaud Miege
2011-4-8
One orifice would represent the inlet orifice, while the second orifice would represent the outlet orifice. I think they need to be connected back to to back so that the same convention for the flow rate is used, but I could be wrong. I'd suggest trying with the orifices back-to-back and also in the same direction to see the impact on the simulation results. It should be clear which one is incorrect.
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