PUREair Protection Against Hot Gas Ingestion

Hot Gas Ingestion, or HGI, is a phenomenon where the engine exhaust gases are re-ingested into the engine air inlet.


HGI is a common phenomenon that occurs when helicopters hover with a tail wind or during sideways or rearwards flight.


HGI causes increased engine inlet gas temperatures and potential flow/temperature distortion. Assuming an engine is operating at its maximum rated temperature, an inlet temperature rise of 40°F due to HGI can cause approx 15 percent power loss. In addition, spatial or temporal temperature distortion can cause compressor stall, which in turn may lead to abrupt and catastrophic power loss.

The Solution

With the PUREair system, the ingested hot gas is quickly and uniformly redistributed by the swirling process inside the vortex tubes, resulting in uniform, stable air flow into the engine intake. By reducing flow and temperature distortion, this minimizes any detrimental effects of HGI and hence significantly alleviates compressor stall problems.

Computational Fluid Dynamics (CFD) illustrations 

Figure 1
Figure 2
   20mm from the engine air inlet, a pocket of hot gas forms.

Figure 3 - Without a PUREair system at the compressor entry plane, this gas pocket creates temperature distortion, with all its associated effects.
Figure 4 - With a PUREair system, the hot gas mixes with fresh air resulting in an even temperature distribution at compressor entry plane.
The Ultimate in Helicopter Engine Protection
PUREair - The Ultimate in Helicopter Engine Protection
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PUREair systems offers the ultimate in helicopter engine protection
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