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-   -   Stator tip gap at hub in turbogrid /CFX post turbo (http://www.cfd-online.com/Forums/cfx/22596-stator-tip-gap-hub-turbogrid-cfx-post-turbo.html)

Adam May 24, 2006 10:20

Stator tip gap at hub in turbogrid /CFX post turbo
 
Does anyone know how to add a stator tip gap at the hub in turbogrid? Currently turbigrid will only allow a tip gap at the shroud.

One way to get round it is to rename the hub.curve, shroud.curve as each other and also to reverse the profile order in the profile.curve file. This allows a tip to be added at the shroud, which is technically the hub.

However, if you do that, you cannot initialise the stator domains in CFX post turbo mode as the hub and shroud are in the wrong place.

Does anyone know how to get round this, either in turbogrid or in CFX Post so that I can start turbo mode and get the performance data etc?

Thanks

Adam

michel May 29, 2006 04:47

Re: Stator tip gap at hub in turbogrid /CFX post t
 
In CFX Post, you can change the hub and shroud as well. After the initial initialization fails, go to the stator component, select the appropriate shroud surface for hub and vice versa, and press "initialise". This usually works, though occasionally causes Post to crash.

As Post is very tedious to work with, and also quite limited when it comes to turbomachinery analysis other than getting flow field pictures, the easiest way to obtain performance data is to write your own macro. With a macro you can easily circumvent the hub/shroud issue, and have it calculate e.g. overall performance data, radial profiles and meanline data. Those results can then be read into excel or whatever you prefer. This also allows you to plot profiles from different runs in one graph and change the axis range (other simple and necessary things Post cannot do).

By the way, CFX people seem to have realized there is something like a stator gap, and it will be included with the next Turbogrid version.

Cheers, Michel


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