National Institute of Technology Karnataka, Surathkal
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Simulation of Exhaust Duct


The reduction of engine specific fuel consumption (SFC) is a major impetus in the development of aero-engines and the aerodynamic performance of the exhaust system is fundamental to this drive. A lot of heat energy is lost through the exhaust duct in the form of radiations which leads in decreased efficiency of the engine. To compensate the loss SFC of the engine increases.


We used CATIA to design and modify the geometry of the exhaust duct by taking the parameters from different research generals and various books.

Thermal analysis of the duct was done using the ANSYS.


We started by designing a few exhaust ducts by taking parameters from different research papers. One of the models designed is shown in the figure below.

We analysed all the ducts in Ansys using static thermal analysis. The following parameters were used for the analysis:
1. Inlet temperature: 800 C
2. Outlet temperature: 300 C
3. Heat flow: 1000W at the cross-section of inlet.
4. Internal heat generation: 1000W
5. Film Coefficient:2500 W/(m^2 .K)
6. Radiation emissivity is 0.8W/(cm^2.micron)
7. Ambient Temp. :550 C
We got the following result of the analysis:-

After going through the results we modified the initial geometry by adding holes near the outlet of the duct which resulted in the following geometry.

We again performed the analysis using the same parameters and got the following result:-


The heat distribution pattern is almost uniform now which will result in fewer heat radiations. This will reduce the SFC of the engine


By modifying the design and adding holes near the outlet of the duct we observe that the pattern of heat distribution is almost uniform.


Try to minimise the radiation by using different materials for making the exhaust duct. Optimising the exhaust duct by means of the CFD technique, which deals with various types of heat and fluid flow problems.


1. Ansys Icem Cfd 12.0, User Guide,, 2009.
2. Frick, C. W., Davis, W. F., Randall, M. R., Mossman, E. A., An Experimental Investigation of NACA Submerged-Duct Entrances, NACA-ACR-5I20, 1945.
3. Stalewski, W., Parametric Modelling of Aerodynamic Objects – The Key to Successful Design and Optimisation, Proceedings of CEAS, The International Conference of the European Aerospace Societies, Venice, Italy 2011


● Shefin S -
● Meghana R -
● Sashi Sekharan -
● Abhinav Raj -