Post by racket on Jan 7, 2016 15:45:39 GMT -5
Hi Mikko
Yeh, that HT100 is like the extra large frame Garretts , very expensive and rather rare, I remember trying to get info on the HT100 but like those very big Garretts , there just ain't none around.
The C20 wheel in the heli engine turns out ~210 HP (420 hp output from both 3rd and 4th stage combined), with 3.6 lbs/sec mass flow .
Now if you didn't mind some extra losses it'd probably be possible to squeeze 4 lbs/sec through one , it all depends on what sort of pressures and temperatures you have coming out of the gas producer, unfortunately most turbo based engines output energy will be limited because of the component efficiencies, the lower the interstage pressure the less flow will pass through the freepower as the gas speeds produced by the lower pressure drop will also be lower, it just physically can't get through fast enough.
With turbos and most of our turbine engines, as the flow increases the weight goes up much faster , if we double flow the weight might go up 4 times , so some of those big turbos are very heavy , the GT6041 is a heavyweight even with its alloy comp housing , those cast iron comp housings ones must be extremely heavy units.
~100 mm seems to be the "unofficial" upper limit for the mass produced units , 106mm for a few , but only aftermarket upgrades above that , the very big diesel engines simply fit multiples of "small" units , its cheaper and gives a certain amount of maintenance benefits over a single massive turbo as used on gigantic shipping diesel engines
I had a look at the Holset Site yesterday and they're starting to put more info on it , but I still couldn't find actual wheel sizes unlike the Garrett Site which is much more forthcoming .
With the Chinese HX80-82 turbos , if they are direct copies and have the same sized wheels, bearings etc , it would always be possible to upgrade one using better quality turbine material , they seem to use a 950 degree C material whereas Inco 713C gives another 100 C degrees of safety buffer , you could always machine out the comp housing to take a larger billet comp wheel like the X846 that Anders will be using or even the X831 that I'm using if you don't mind the extra work of also modifying the turb exducer.
The X846 wheel with its 106.56 mm inducer , 152.04mm exducer is a nice match for the 4th stage Allison freepower wheel, the flow at "modest" P2 pressure ratios is OK with the freepower whilst at higher P2s the freepower can still cope because of the extra interstage pressure .
My X831 comp wheel has a tad too much flow for the "common" 4th stage C20 wheel and is the reason why I'm having to look at using the bigger "rarer" C30 4th stage wheel .
Cheers
John
Yeh, that HT100 is like the extra large frame Garretts , very expensive and rather rare, I remember trying to get info on the HT100 but like those very big Garretts , there just ain't none around.
The C20 wheel in the heli engine turns out ~210 HP (420 hp output from both 3rd and 4th stage combined), with 3.6 lbs/sec mass flow .
Now if you didn't mind some extra losses it'd probably be possible to squeeze 4 lbs/sec through one , it all depends on what sort of pressures and temperatures you have coming out of the gas producer, unfortunately most turbo based engines output energy will be limited because of the component efficiencies, the lower the interstage pressure the less flow will pass through the freepower as the gas speeds produced by the lower pressure drop will also be lower, it just physically can't get through fast enough.
With turbos and most of our turbine engines, as the flow increases the weight goes up much faster , if we double flow the weight might go up 4 times , so some of those big turbos are very heavy , the GT6041 is a heavyweight even with its alloy comp housing , those cast iron comp housings ones must be extremely heavy units.
~100 mm seems to be the "unofficial" upper limit for the mass produced units , 106mm for a few , but only aftermarket upgrades above that , the very big diesel engines simply fit multiples of "small" units , its cheaper and gives a certain amount of maintenance benefits over a single massive turbo as used on gigantic shipping diesel engines
I had a look at the Holset Site yesterday and they're starting to put more info on it , but I still couldn't find actual wheel sizes unlike the Garrett Site which is much more forthcoming .
With the Chinese HX80-82 turbos , if they are direct copies and have the same sized wheels, bearings etc , it would always be possible to upgrade one using better quality turbine material , they seem to use a 950 degree C material whereas Inco 713C gives another 100 C degrees of safety buffer , you could always machine out the comp housing to take a larger billet comp wheel like the X846 that Anders will be using or even the X831 that I'm using if you don't mind the extra work of also modifying the turb exducer.
The X846 wheel with its 106.56 mm inducer , 152.04mm exducer is a nice match for the 4th stage Allison freepower wheel, the flow at "modest" P2 pressure ratios is OK with the freepower whilst at higher P2s the freepower can still cope because of the extra interstage pressure .
My X831 comp wheel has a tad too much flow for the "common" 4th stage C20 wheel and is the reason why I'm having to look at using the bigger "rarer" C30 4th stage wheel .
Cheers
John
Wheel sizes stated 100/152mm comp and 112/129mm turbine.
Haven't decided yet what kind of gas producer unit I'll make, so I don't dare to buy your wheel yet...
