Why is my Simscape gas fan simulation so incredibly sensitive to temperature and flow resistance?

6 次查看(过去 30 天)
I am doing a relatively simple simulation in Simscape with a fan, some pipes, a heat exchanger etc. (and a bunch of sensors) simulating helium at T=20K P=20bar.
I have robust fluid properties entered across the entire operating range that I am simulating.
If I initialize at say 20K everything runs smoothly and the temperature may fluctuate between 15K & 25K depending on the heat loads etc. HOWEVER, if I attempt to INITIALIZE at 25K or even 22K, the simulation won't converge to initial conditions!
Additionally, if I change the flow resistance of my circut slightly then the entire simulation may not initialize.
I am commanding the pump with a ramp speed input from an ideal angular velocity source (as below) usually starting at 0 speed (but this doesn't seem to change the initialization success much):
The error is always this:
Does anyone have reccomendations for how to deal with these issues?
Is there some trick to getting the fan to operate more robustly?
Is there a better solver setting I should be using (I have tried starting from steady state and not starting from steady state).
  6 个评论
Colin O'Shea
Colin O'Shea 2020-7-19
With regards to the density, the reference density is that which you used to calculate the input vectors for fan data (flow The block will interpolate the density vector in your material properties and scale the fan vectors by this new density as tempreature changes. It is equivalent to other blocks requiring a reference temperature and scaling the calculated values by the interpolated material properties.
zhuo chen
zhuo chen 2020-8-28
Thank you very much for your answer. I want to simulate a constant temperature field. How can the density not change with the temperature through the setting, or the temperature of the system does not change, can it be achieved by changing the insight of the material?

请先登录,再进行评论。

回答(1 个)

Juan Sagarduy
Juan Sagarduy 2020-10-26
Hello Colin,
I think that Starting from Steady State can be a difficult choice to start with.
I would recommend that you start with a simple system: fan, source reservoir, a pipe and a sink reservoir.
Pressure for both reservoirs is equal and transfer of gas is done through spinning the fan.
BR Juan

类别

Help CenterFile Exchange 中查找有关 Gas Models 的更多信息

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by