Turbine Map using R line (Beta Coordinate) in T-MATS

[Alireza Ebrahimi]

Dear Jeff

I'm using T-MATS to simulate a twin-spool gas turbine engine.

I have a turbine map data (from GasTurb software) using R line and Nc to compute PR, EFF, WC (similar to the compressor), but in T-MATS, it used PR vector and NC vector to compute EFF and WC.

I really have a problem because the PR vector should be [n*1] vector always. in some special cases, it should be [n*m] vector (m is the number of EFF or WC data in each  speed line)

Then I changed the PR vector to [n*m], but the simulation is not converging anymore.

How can I use Rline in the Turbine module (like compressor)?

Assume that I have PR, EFF, WC vector as well.

Thank you very much

[J Chapman]

Milad,  

I think you have two options... both require a fair amount of re-writing of components.  The first is to rework the compressor block to become a turbine..  the formulation of the Rline map is already in there, so the map look up stuff would easy,  you would need to change how the block was working... example make it loose pressure rather than gain pressure, rework the bleed flows to take flow in rather than remove them.The second option is the redo the turbine block to accept a different map.  In the turbine there are variables EffMap, WcMap.  These would need to be redefined,  you would also need to add in inputs for Rline and add in any other map stuff you might want. Either of these methods require a bit of work to understand how it was put together.  As in the simulink block (utilizing mask) and  S-functions (making use of tlc files and c files, which are compiled to mex).

You don't need to do all that though,  the GasTurb map can be converted to T-MATS format with some data manipulation. I actually have already done it,  but unfortunately have not released the code, so can't share it at the moment. Essentially, just ignore the Rline,  create a script that reads in the map then uses it to generate your T-MATS map (process is similar to that shown in the NPSStoTMATS_Tool or CreateMaps_NPSS_Rline.m under the TMATS_Tools folder). The main reason to use a Rline is that you can get some numbers that repeat.  For example a certain PR can have two Nc values, so given those two values you wouldn't know what efficiency you have, which make something like an Rline necessary.  This doesn't really happen with the turbine.

Let me know if this helps,  I can look into releasing the GasTurb to TMATS map translating code If you aren't having luck and if there is interest.

-Jeff

[Mike Corbett]

Milad,

Two additional thoughts:

1) To elaborate a tad on Jeff's suggestion where you modify the turbine block, you'll still need to sort out where Simulink is checking dimensions and the way the block mask is written, but you can calculate beta on the fly. A GasTurb turbine map has two additional 1-D tables for PRmin and PRmax as a function of Nc. So you still feed PR into the top level turbine block but then pass it to those two tables and then calculate beta=(PR-PRmin)/(PRmax-PRmin). Now, with the beta you just calculated, use tables in the GasTurb format.

2) If you have the GasTurb suite (or whatever they call it) that gives you SmoothT as well, you can load your GasTurb turbine map into that, turn the crank on it just a tad and then have it output "Synthesis Tables w/o Beta" which is a text file containing tables of Wc and eff as functions of Nc and PR.

-Mike

[姜继明]

Hi,

I am working to create a Turboshaft model with T-MATS!

I had some problems when I tried to set the boundary conditions for the Convergent nozzle.The default behavior is to perform an ' MNexit=1' to  ensure maximum outlet air velocity. That will maximize the thrust. I want to change the boundary condition to 'Psexit=Pamb'. Then, exhaust gas energy decreases and power generated from turbine will increase.

I really hope to get your help. I'm looking forward to hear from you.

Have a great day,

Ming

[姜继明]

Hi,

I am working to create a Turboshaft model with T-MATS!

I had some problems when I tried to set the boundary conditions for the Convergent nozzle.The default behavior is to perform an ' MNexit=1' to  ensure maximum outlet air velocity. That will maximize the thrust. I want to change the boundary condition to 'Psexit=Pamb'. Then, exhaust gas energy decreases and power generated from turbine will increase.

I really hope to get your help. I'm looking forward to hear from you.

Have a great day,

Ming