Stiggy Pop
In the cool kids club
- Joined
- Feb 27, 2011
- Location
- Granville, MA
Radial turbines generate shaft power via momentum transfer from the exhaust gas, but expansion ratio (inlet pressure/outlet pressure) plays an important part. By allowing the outlet flow to expand in a diverging nozzle you can reduce the expansion ratio needed to produce the required amount of shaft power at a given mass flow rate. Lower post-turbine pressure then results in lower pre-turbine exhaust backpressure. Helps improve engine VE reducing restriction, allows for more timing advance before the knock threshold, gets your exhaust manifold pressure down closer to intake manifold pressure; all good stuff.
thanks for taking the time to explain it, learn something new every day!