CFD-Post results analysis

Edgar Yako · April 28, 2021, 17:01

Hello,

I have simulated a radial compressor within ANSYS by firstly using VISTA CCD and consequently transferring the data into Turbomachinery Fluid Flow. Here, BladeGen creates the 3-D model of the radial compressor, turbogrid creates the mesh and finally CFX provides the results.

My question is regarding some of the different results that CFD-post automatically generates and wanted to know whats the difference between them. The attached pictures are below. What would be the difference between these 3? (Span 10,50,90 view)

https://imgur.com/7WjAX86

https://imgur.com/xFBwElM

https://imgur.com/lpfmfNv

Also, what do you think of these results? These gave an isentropic efficiency of 86% and a pressure ratio of 4.7 overall but I want to understand whether these velocity distributions along the suction and pressure side are reasonable or they do not look efficient.

I will also add a blade-to-blade view image in case its required.

https://imgur.com/lGBvNKz

Thanks in advance

Edgar

ghorrocks · April 28, 2021, 19:41

Please post images directly on the forum. Do not use third party sites. See FAQ: https://www.cfd-online.com/Wiki/Ansy...n_the_forum.3F

About accuracy, see FAQ: https://www.cfd-online.com/Wiki/Ansy..._inaccurate.3F

On interpreting your results - I have no idea what you are modelling, what conditions you are modelling or what the images show. This means I cannot make any useful comment about what your results are.

Edgar Yako · April 29, 2021, 06:20

Sorry I should have been clearer with my modelling.

I am trying to design a radial compressor that achieves a reasonable isentropic efficiency. The specifications added to Vista CCD are the following:

Duty and Aerodynamic Data Tab
Overall Pressure ratio :4.5
Mass flow rate : 0.2 kg/s
Rotational Speed : 150000 rpm
Temperature inlet:293.15K
Pressure : 101000 Pa
Isentropic Efficiency: 0.8
(Everything else left default)

Geometry Tab
Hub diameter : 20 mm
Shroud Diameter : Optimized diameter
Number of vanes : 7 (for both main vane and intervane)
(Everything else left default)

After setting up Vista CCD, I transferred the data into Turbomachinery Fluid Flow which is a pre-built program within ANSYS that automatically generates the mesh using Turbogrid (it is a hexahedral mesh with 250000 total nodes), consequently, it uses CFX to set the parameters for simulation and finally the results are obtained on CFD-Post. The results I have shown you are obtained within CFD-Post and there are different tabs that are automatically generated. However, I was not sure why there are 3 different types of results (Span 10/50/90) and wanted to know what these referred to.

If you need anything else in particular to continue please let me know. Also, do you need me to re-submit the images or can you use those links?

April 28, 2021, 17:01	CFD-Post results analysis	#1
Edgar Yako New Member Edgar Join Date: Mar 2021 Posts: 5 Rep Power: 5	Hello, I have simulated a radial compressor within ANSYS by firstly using VISTA CCD and consequently transferring the data into Turbomachinery Fluid Flow. Here, BladeGen creates the 3-D model of the radial compressor, turbogrid creates the mesh and finally CFX provides the results. My question is regarding some of the different results that CFD-post automatically generates and wanted to know whats the difference between them. The attached pictures are below. What would be the difference between these 3? (Span 10,50,90 view) https://imgur.com/7WjAX86 https://imgur.com/xFBwElM https://imgur.com/lpfmfNv Also, what do you think of these results? These gave an isentropic efficiency of 86% and a pressure ratio of 4.7 overall but I want to understand whether these velocity distributions along the suction and pressure side are reasonable or they do not look efficient. I will also add a blade-to-blade view image in case its required. https://imgur.com/lGBvNKz Thanks in advance Edgar

April 28, 2021, 19:41		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	Please post images directly on the forum. Do not use third party sites. See FAQ: https://www.cfd-online.com/Wiki/Ansy...n_the_forum.3F About accuracy, see FAQ: https://www.cfd-online.com/Wiki/Ansy..._inaccurate.3F On interpreting your results - I have no idea what you are modelling, what conditions you are modelling or what the images show. This means I cannot make any useful comment about what your results are. aero_head likes this. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

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April 29, 2021, 06:20		#3
Edgar Yako New Member Edgar Join Date: Mar 2021 Posts: 5 Rep Power: 5	Sorry I should have been clearer with my modelling. I am trying to design a radial compressor that achieves a reasonable isentropic efficiency. The specifications added to Vista CCD are the following: Duty and Aerodynamic Data Tab Overall Pressure ratio :4.5 Mass flow rate : 0.2 kg/s Rotational Speed : 150000 rpm Temperature inlet:293.15K Pressure : 101000 Pa Isentropic Efficiency: 0.8 (Everything else left default) Geometry Tab Hub diameter : 20 mm Shroud Diameter : Optimized diameter Number of vanes : 7 (for both main vane and intervane) (Everything else left default) After setting up Vista CCD, I transferred the data into Turbomachinery Fluid Flow which is a pre-built program within ANSYS that automatically generates the mesh using Turbogrid (it is a hexahedral mesh with 250000 total nodes), consequently, it uses CFX to set the parameters for simulation and finally the results are obtained on CFD-Post. The results I have shown you are obtained within CFD-Post and there are different tabs that are automatically generated. However, I was not sure why there are 3 different types of results (Span 10/50/90) and wanted to know what these referred to. If you need anything else in particular to continue please let me know. Also, do you need me to re-submit the images or can you use those links?