# Modeling engine effects

 User Name Remember Me Password
 Register Blogs Members List Search Today's Posts Mark Forums Read

 September 14, 2005, 11:41 Modeling engine effects #1 Riaan Guest   Posts: n/a My question is about modeling the effect of a gas turbine on the flow through an intake duct. I have an intake duct, turbine and exhaust duct in a standard configuration: Intake Duct volume --> Boundary Condition Face --> Turbine Volume (empty, not meshed) --> Boundary Condition Face --> Exhaust Duct volume What B.C should I use at the end of the Intake duct volume - I know the massflow that the turbine requires, but not the Static Pressure or Total Pressure at this face. What B.C for the inlet face of the Exhaust Duct? -Thanks Riaan

 September 15, 2005, 03:20 Re: Modeling engine effects #2 Razvan Guest   Posts: n/a Do you want to MODEL the turbine, not actually calculate it (I mean you do not want to insert real turbine geometry in the middle volume and take its effects into account by simply imposing BC on the two faces)? Razvan

 September 15, 2005, 07:44 Re: Modeling engine effects #3 Riaan Guest   Posts: n/a No, I don't want to model the turbine, just have a "black box" with inlet and exit b.c. similar to what a turbine would generate.

 September 15, 2005, 14:00 Re: Modeling engine effects #4 Razvan Guest   Posts: n/a Let me explain myself: - MODELING = taking into account the possible effects of a certain geometry by analitical means, approximating it with a mathematical model, actually deliberately imposing not calculating its properties; - SIMULATING = considering real geometry, calculating effects by imposing conditions on boundaries away from actual object. So, what you're trying to do is MODEL the turbine, not SIMULATE it! Concerning your problem, the only way I can imagine solving it is this: - eliminate first and second volume and keep only exhaust pipe with turbine exit as inlet condition - calculate by hand or using a mathematical program the radial distribution of fluid's thermodynamic properties based on specific turbomachinery relations - input these radial profiles as BC at the inlet boundary - obtain solution. Of course, you will have to repeat steps 2-4 for every mass flow you need to consider. Best wishes, Razvan

 September 19, 2005, 08:24 Re: Modeling engine effects #5 Riaan Guest   Posts: n/a Found easier way. Set Mass-flow inlet B.C. at the turbine inlet face, with the mass-flow vector pointing "into" the turbine. Since this is a subsonic case, pressure values on the b.c. face will be interpolated from the cells next to the b.c. Anycase, agree on difference between modeling and simulating. Quick and dirty forum post - sorry.

 September 20, 2005, 17:45 Re: Modeling engine effects #6 Riaan Guest   Posts: n/a Running into problems - seems the Mass-flow inlet creates a local strong shock in the exit plane...M>2...don't know why yet?

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post anatoliafire Main CFD Forum 0 May 3, 2010 02:40 Majid FLUENT 0 August 2, 2009 09:04 TWaung CFX 2 March 29, 2009 18:42 Abdel-Fattah M. Mahrous CD-adapco 1 April 23, 2005 01:13 Zamir Main CFD Forum 10 November 24, 2004 04:18

All times are GMT -4. The time now is 13:40.

 Contact Us - CFD Online - Top