I'm not looking for performance improvements at this point, just some discussion if anybody has some information.
For the turbine housing A/R calculation, the area used is the area right at the tongue entering the volute. Also looking at the housing, it has what I would call a “radial nozzle” (not sure what it is actually called) , it is a passage that runs around the entire circumference except for the tongue. Is this area equal, greater, or less than the area used for the A/R calculation? It is understandable how the A in the A/R impacts gas velocity and the R impacts swirl for a given housing type. These items will affect the velocity impacting the wheel. In turn affecting spool up and turbine flow capability. How is the “radial nozzle” area set. Also, since our typical housings have no guide vanes, the features referenced above seems to be the major factors the housing contributes to the turbo’s performance, are there others?
As the housing limits are approached, at what gas velocity as a ratio to sonic velocity, does the housing start to limit performance?
Anybody know ideally how much of the pressure drop is taken through the housing until it enters the wheel and how much is taken through the wheel on a proportional basis? The wheel is typically a combination of impulse and reaction. A 100% impulse wheel would use only velocity to drive it(very little pressure drop) and a 100% reaction wheel would use pressure drop to drive. In most cases, the single stage centrifugal turbine we use has a combination. In a well matched wheel and housing will the housing choke first?
Since the housing has a cast surface finish, any benefit to having the housing polished? Since you are using wasted energy, and in many cases exhaust is being bypassed, my guess is not too much. But it could possibly provide some if pushing hard.
For the turbine housing A/R calculation, the area used is the area right at the tongue entering the volute. Also looking at the housing, it has what I would call a “radial nozzle” (not sure what it is actually called) , it is a passage that runs around the entire circumference except for the tongue. Is this area equal, greater, or less than the area used for the A/R calculation? It is understandable how the A in the A/R impacts gas velocity and the R impacts swirl for a given housing type. These items will affect the velocity impacting the wheel. In turn affecting spool up and turbine flow capability. How is the “radial nozzle” area set. Also, since our typical housings have no guide vanes, the features referenced above seems to be the major factors the housing contributes to the turbo’s performance, are there others?
As the housing limits are approached, at what gas velocity as a ratio to sonic velocity, does the housing start to limit performance?
Anybody know ideally how much of the pressure drop is taken through the housing until it enters the wheel and how much is taken through the wheel on a proportional basis? The wheel is typically a combination of impulse and reaction. A 100% impulse wheel would use only velocity to drive it(very little pressure drop) and a 100% reaction wheel would use pressure drop to drive. In most cases, the single stage centrifugal turbine we use has a combination. In a well matched wheel and housing will the housing choke first?
Since the housing has a cast surface finish, any benefit to having the housing polished? Since you are using wasted energy, and in many cases exhaust is being bypassed, my guess is not too much. But it could possibly provide some if pushing hard.