ripcrow
Veteran Member
Joined: December 2015
Posts: 114 
|
Post by ripcrow on Feb 13, 2016 4:50:03 GMT -5
Just ordered a garret gt3037 turbo. The specs say oil and water cooled with a wet float bearing. What pressure or amount if oil do I need to pump thru thus turbo. Inducer us 57 mm with a 56 trim turbine exducer is 60 mm with a trim of 84 and ar of .82.
|
|
|
|
Post by racket on Feb 16, 2016 22:47:09 GMT -5
Don't worry about the water , just keep the oil pump going for several minutes after shutdown to remove the heat that the water is normally there to remove after stopping the engine so as to prevent heat soakback to the bearings with its attendant oil coking potential .
You'll be needing 3 or 4 litres/minute capacity of oil supplyto be on the safe side , you'll probably only need ~ 2 lpm but it never hurts to have some extra , the main thing is to keep at least 45-50 psi at the turbo oil inlet at all times, easy to do with cold oil , but you need flow capacity with hot thin oil .
|
|
|
|
Post by smithy1 on Feb 17, 2016 3:25:54 GMT -5
Wot John said....the more capacity you have...the less chance of something going astray when the oil is hot.
Smithy.
|
|
ripcrow
Veteran Member
Joined: December 2015
Posts: 114
|
Post by ripcrow on Feb 17, 2016 22:09:58 GMT -5
Thanks. Has anyone tried using a diesel injector in a jet. I can get some old injectors and adjust them to open at 100 psi so my efi pump can supply them. They were designed to operate at 2600 psi so I'm not sure on atomisation. I hope to run my jet on vegetable oil eventually so a deisel injector would be handy.
|
|
|
|
Post by enginewhisperer on Feb 17, 2016 23:56:19 GMT -5
as far as I understand, most diesel injectors (on indirect injection engines) don't actually atomise the fuel themselves. They shoot a thin stream of very high pressure fuel at a surface to atomise it.
|
|
|
|
Post by madpatty on Feb 18, 2016 12:52:33 GMT -5
Hi.
I once tried using diesel fuel injectors by adjusting their spring to open at nearly 100-150 psi.
Not a very good option if appeared to me as i think they are not for continuous operation(they are good for intermittent operation only).
Even when the spring was light , it tend to close the fuel injector thus putting a lot of load on my gear pump i was using.
And moreover the atomisation was not so good.
So my thoughts,
Why to use injectors when you have got suitable fuel nozzles and enough pressure.
Cheers.
|
|
|
|
Post by smithy1 on Feb 18, 2016 15:14:47 GMT -5
I believe diesel injectors use differential internal pressures to help open and close the pintle valves, the newer "common rail" types are electronically controlled, I doubt they flow enough for our applications anyway, without major modifications.
You can get high flow "petrol/gasoline" injectors, I've often thought of using one but most of them have plastic housings...I suspect they're not a good idea in a hot turbine engine.
Would be interesting to see what sort of spray pattern and flow rates can be achieved with modest ~100psi fuel pressures though.
I have a single "doctored" Allison/Rolls-Royce C20B fuel injector in my GT6041 engine....I'm running ~150-160psi at max flow...appears to work OK thus far, It's not perfect but plenty good enough to run the engine, was just a matter of doing the math and adjusting the internals to arrive at the correct flow vs pressure required for the engine.
Smithy.
|
|
ripcrow
Veteran Member
Joined: December 2015
Posts: 114
|
Post by ripcrow on Feb 19, 2016 7:25:59 GMT -5
I can obtain the injection pump to suit the injectors. Thinking about using 1-2 injectors and the injection pump feeding into one common feed line. By backing pressure Down a bit and revving the injector pump up I wonder if the pulses would even out. Set the governor to full open and throttle the engine by restricting the return line. Not sure how much horsepower a injection pump needs though.
|
|
ripcrow
Veteran Member
Joined: December 2015
Posts: 114
|
Post by ripcrow on Feb 19, 2016 7:29:06 GMT -5
Hi. I once tried using diesel fuel injectors by adjusting their spring to open at nearly 100-150 psi. Not a very good option if appeared to me as i think they are not for continuous operation(they are good for intermittent operation only). Even when the spring was light , it tend to close the fuel injector thus putting a lot of load on my gear pump i was using. And moreover the atomisation was not so good. So my thoughts, Why to use injectors when you have got suitable fuel nozzles and enough pressure. Cheers. I don't have fuel nozzles. Can you explain |
|
|
|
Post by madpatty on Feb 19, 2016 11:17:02 GMT -5
|
|
|
|
Post by racket on Feb 19, 2016 20:38:45 GMT -5
Hi
If you eventually want to use vegetable oil then you'll probably be needing high fuel pressure for good atomisation , fuel pressure of ~500 psi and using a 3 GPH (rated @ 100 psi) hollow cone oil burner spray nozzle to supply the required ~6.5 GPH of fuel
If you can get a pump to supply that quantity at that pressure there'll be a nozzle to suit.............but don't try using lower fuel pressures , the poor atomisation will only cause problems unless you have a very large combustor with plenty of dwell time for the burn to take place before reaching the turbine wheel .
Cheers
John
|
|
ripcrow
Veteran Member
Joined: December 2015
Posts: 114
|
Post by ripcrow on Feb 21, 2016 5:47:13 GMT -5
Well at least no one laughed at the vegetable oil. I'm thinking of making the combustor 1/2 as long again as is required (30 cm now 45 cm ) to allow a longer burn better heating of air also. I think a 500 psi fuel pump would be quite expensive if I could even find one and driving it just complicates things again. Want to power it up with 12-24 volt system only. I'm thinking of also putting swirl vanes inside the combustor so the air enters and is forced to begin a circular path around the combustor. Just some flat steel welded the length of the tube deflecting the air as it enters. Any thoughts.
|
|
|
|
Post by racket on Feb 21, 2016 15:52:59 GMT -5
Hi
Theres a 12 volt hydraulic power unit for a Toyota MRS sports car as well as hydraulic trims for boats that might provide a suitable high pressure fuel pump, the amount of fuel you'll be burning wouldn't require much power to produce 500 psi .
You only need air swirl vanes around your fuel injector , don't fit anything down further where the heat from combustion could affect them and cause them to go through the turbine .
Cheers
John
|
|
ripcrow
Veteran Member
Joined: December 2015
Posts: 114
|
Post by ripcrow on Feb 25, 2016 17:38:03 GMT -5
Zthanks for the tips. I'll check them out. I hate living on a budget. Has anyone tried preheating the air between comp and combustor. Could the air be directed over the exhaust pipe through a heat exchange box type of thing then into the combustor. From what I understand the hotter the incoming air the better the fuel effiency. I not sure if taking heat Off the free power flow is a good idea or if it would even make any difference
|
|
|
|
Post by racket on Feb 25, 2016 17:51:58 GMT -5
LOL, living on a budget does limit what we can do, it just takes a bit longer to reach our goals :-(
Yep , adding heat to the comp discharge air from some sort of HX using exhaust gases will greatly improve your specific fuel consumption , probably halve it if the HX is efficient enough.
If using the freepowers exhaust gases there will be a shaft horsepower penalty due to the "restriction" of the HX reducing the pressure ratio across the freepower stage , but it needn't be more than 10% or so loss , but well worth it for the big reduction in fuel burn rates if thats a priority.
Cheers
John
|
|
