I have been twinking my spreadsheet some more.

Building Hohn's Dream set-up?

Assumed Parameters
HP 450
BSFC 0.38
AFR 26
CE 65 %
IE 76 %
VE 95 %
Air Filter Diff Press 0.20 psi
IC Diff Press 3.00 psi
Ambient Temp 75 F
Ambient Press 24 Inch Hg
RPM 3200
Summer 7.2 Lbs/Gal
Winter 6.9 Lbs/Gal
Turbine Inlet Temp 1200 F

Air Flow
Comp Outlet Temp 564 F
IC Outlet Temp 192 F
Density Ratio 3.9
Pressure Ratio 5.1
Air Flow 1291 CFM
Air Flow 76.8 Lb/Min
Compressor Hp 416

Air Fuel Ratio
Fuel Flow 171 Lb/Hr
Fuel Flow 2.9 Lb/Min
Summer 23.8 Gal/Hr
Winter 24.8 Gal/Hr

Required Air Flow
Air Flow 1245 CFM
Air Flow 74.1 Lb/Min
Boost 48 psi

Corrected Exhaust Flow
Corrected Exhaust Flow 142.5 Lb/min


-OR- my truck chugging down the highway

Assumed Parameters
Vehicle Speed 60 MPH
Grade 0 Percent
Rolling Resistance Coefficient 0.0125
Frontal Area of Truck 38.5 Square Feet
Truck Wind Drag Coefficient 0.44
Weight of Truck 7600 Lb
Frontal Area of Trailer 20 Square Feet
Trailer Wind Drag Coefficient 0.95
Weight of Trailer 3000 Lb

Horse Power Requirements
Truck Hp 55
Trailer Hp 37
Total Hp 91

Fuel Ecomomy
MPG 14.8 Summer
MPG 14.2 Winter

Assumed Parameters
HP 91
BSFC 0.32
AFR 28
CE 65 %
IE 76 %
VE 95 %
Air Filter Diff Press 0.00 psi
IC Diff Press 0.00 psi
Ambient Temp 75 F
Ambient Press 26 Inch Hg
RPM 1600
Summer 7.2 Lbs/Gal
Winter 6.9 Lbs/Gal
Turbine Inlet Temp 900 F

Air Flow
Comp Outlet Temp 156 F
IC Outlet Temp 95 F
Density Ratio 1.3
Pressure Ratio 1.4
Air Flow 221 CFM
Air Flow 14.2 Lb/Min
Compressor Hp 7

Air Fuel Ratio
Fuel Flow 29.12 Lb/Hr
Fuel Flow 0.5 Lb/Min
Summer 4.0 Gal/Hr
Winter 4.2 Gal/Hr

Required Air Flow
Air Flow 211 CFM
Air Flow 13.6 Lb/Min
Boost 5 psi

Corrected Exhaust Flow
Corrected Exhaust Flow 23.8 Lb/min


Nothing too useful of course, but I am wondering if I am even close?

Jim

 

Oh Good Lord. He has been infected with the incurable HOHNitis. It looks to be a bad case too. Seeking help is the first step. But as long as you're sick with it, keep writing.

 

Yeah, sorry....

It helps me understand some things and kills some dead time at work.

I think my compressor Hp number is a bit high, not sure. I mean in Hohn's case 400 some compressor Hp to support 450 some engine Hp. The compressor is moving allot of air at pressure, but does that number seem close?

The latest project on my spread sheet is exhaust gas enthalpy. I plan to try to put something together that can predict the available Hp potential for the turbine base upon enthalpy present in the exhaust (btu/lbm). This is to maybe predict turbine Hp / efficient and even possibly / hopefully predict EGT's. That is is a tough nut to crack however, considering enthalpy of moist air. The water vapor, of course, comes from the air injested as well as that formed during combustion.

Anyone know any good leads to go down that trail a bit?

Then again I might toy with excess boost effect on total / net engine Hp or even try to get with some acceleration vs Hp calculations.

Jim

 

WOW that was way over my head. but impressive.
it is good to see we still have evil scientists around here

 

Man, you got way too much time on your hands, get a girlfriend or something

 

Well you got my respect. A wife, a girlfriend and a truck. (Fishing boat?)

You are a better man than me to keep them all happy....

Jim

 

Now, wait a minute. What kind of a trailer is it that has 20 sq ft frontal area? That analysis is biased, please correct that and re-post!
Besides, I can't help but notice that you reduced Hohn't results by running his engine at 24" Hg pressure, and giving yours better respiration at 26". Well, he did run his in WY, so that may be ok...
Ant in the end, who would argue that you need the HP to drive? I thin people simply want the HP to be able to have fun!
-P

 

Must be one of them small 3x6.5 single axle canvas pop-up camper trailers, popular back in the '60's-'70's....................