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The problem of unsteady state calculation of propeller static thrust. |
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March 19, 2014, 00:01 |
The problem of unsteady state calculation of propeller static thrust.
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#1 |
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Xiaohua Li
Join Date: Nov 2013
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I use the Fluent 14 to calculate the propeller static thrust in unsteady state.
boundary conditon: inlet: pressure inlet; outlet: pressure outlet; flowfied cylinder: preussure inlet; Using interface to connect the ratary region and stationary region. tuanblence model: k-e(RNG) Using moving mesh, the ratation speed is 9000r/min the result of the force and moment is consistent with the experimental results. BUt the streamline is strange. Dose anyone have good idear? could you give me a favor? thank you very much! Last edited by liulangdefeng2222; March 20, 2014 at 00:09. |
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March 19, 2014, 06:04 |
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#2 |
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Gonzalo
Join Date: Mar 2011
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May be is the reference frame in which they are calculated. If so, you should use velocity in a stationary reference frame.
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March 19, 2014, 06:17 |
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#3 | |
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Xiaohua Li
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Quote:
thank you very much. Last edited by liulangdefeng2222; March 19, 2014 at 23:58. |
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March 20, 2014, 00:07 |
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#4 | |
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Xiaohua Li
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Quote:
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March 20, 2014, 19:24 |
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#5 | |
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Gonzalo
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Sorry for the late response, I've been a little bussy in thees days. But I don't understand you very well, you want to calculate the static force or the streamlines? Because you said that your results of static force are in agreement with the experimental data an then you said
Quote:
And if you have acces to CFDPost try to plot the streamlines in there and show me what you get. Regards. Gonzalo |
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March 21, 2014, 09:40 |
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#6 | |
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Xiaohua Li
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D300_SMM22353-1-0.jpg
D300_SMM22353-1-01100.jpg 绘图1.jpg Quote:
If you have a good idear, You can also send me an email: lixh0208@sina.com appreciate. |
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March 21, 2014, 18:44 |
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#7 |
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Gonzalo
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Location: Argentina
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One more question, the external velocity of the fluid is zero? If so, the phenomena you are facing could be possible. I mean, if the propeler has a high load, it could absorb fluid from all the surrounding space even the one is behind the plane of the propeller but not under the disk plane. Do I make myself clear? Is rather difficult to explain. This occurs in the case of engines at full power and zero velocity. Then such pattern of streamlines could appear. Let me know if the velocity of the free stream is non zero, and we can find another solution.
But that explains the toroidal streamlines near the plane of the propeller, the other streamlines could apperar for the same reason (zero frestream velocity) but generated by an exchange in momentun by shear forces between the slipstream of the propeller and the stationary fluid, I don't know, it could be possible???? Let me know if we could do something else. Regards Gonzalo |
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March 21, 2014, 20:36 |
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#8 | |
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Xiaohua Li
Join Date: Nov 2013
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Quote:
I have simulate the situation from 3000r/min to 9000r/min, every time, the toroidal streamline appears, Whether it is normal? Thank you so much. |
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March 24, 2014, 20:08 |
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#9 | |
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Gonzalo
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Quote:
One more time, because you never answer me: are you sure thet you used "Velocity in Stn Frame" in CFDPost to plot the streamlines? I hope this helps you, regards. Gonzalo |
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March 24, 2014, 23:59 |
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#10 | |
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Xiaohua Li
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Quote:
I have also simulate the situation that the stream velocity is 20m/s, it just uses several hous to get steady, and has no toroidal streamlines . I am so that I didn't explain clearly, I don't use "Velocity in Stn Frame". Thank you so much for helping me. |
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March 25, 2014, 09:03 |
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#11 |
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Gonzalo
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I'm glad you found you problem, may be that was the first thing that I had to ask you: did your simulation reach a steady state? Hehe, but well you found your problem and solved it. It seems that in the transition to a stady state the toroidal streamlinees apperar and then disappear when the fluid surrounding the slipstream has certain velocity induced by the former, mmm could be possible. Well, CU in another post. Regards.
Gonzalo |
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July 7, 2015, 12:17 |
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#12 |
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Julia
Join Date: May 2011
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Hi
I simulate a propeller in CFX. how can I calculate the thrust ? |
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