Explain a Boot strap type aircraft refrigeration system with a neat schematic diagram and T-S diagram.

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written 7.7 years ago by

teamques10 ★ 64k

Boot strap type aircraft refrigeration system:

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Fig. Boot Strap Aircraft Air Refrigeration System

The ambient air undergoes ramming before the compressor. Assuming isentropic ramming (process 1-2 in figure).
After compression (2-3), the air bled from the main compressor is cooled by ram air in the first heat exchanger or intercooler (3-4).
This air is then compressed further in the secondary or auxiliary compressor (4-5) and is led to the second heat exchanger, again cooled by ram air (5-6).
The air is then expanded in the cooling turbine (6-7) which drives the secondary compressor. This cooled air is then finally sent to the cabin.
This system is preferred for high speed aircrafts and hence the pressure of air after ramming is comparatively high. So a cooling fan is not required since ram air will now automatically flow over the heat exchanger tubes.
Multistage compression with intercooler decreases the compression work for this system and thus in turn improves the C.O.P.

ADD COMMENT EDIT

sir,can we draw the dark lines are isentropic and dash lines are actual and also reverse direction of both isentropic and actual

7.3 years ago by teamques10 ★ 64k