MustangWorks.com : Ford Forums - View Single Post - Calling engineers: Need help with unit conversions

daveGT · 01-29-2003, 02:27 PM

Ah, fluid dynamics. Fun stuff.

Remember, you need to calculate the total head loss (THL) from a system in units of "feet." You gotta watch your units, and write out your entire energy conservation equation based on Bernoulli's equation to avoid unit problems. Been there, friend!

Remember, the (2g) term is just a conversion term to convert your velocity, or kinetic head (v^2) to units of "feet." Likewise the pressure head (p) must be divided by gamma (density of the fluid) to get units of feet. The elevation, or potential head is already in units of feet. Your system losses, friction (hf) must also be in units of feet: hf = friction factor(length)(v^2) / (diameter)(2g) Everything can now be totaled.

You're getting mixed up when you try to combine the flow rate (Q = v * A) with Bernoulli. Write out Bernoulli, sovle for the velocity at the open end of the pipe, then calculate flow (Q). Then you can convert your flow (Q) anything you want.

Gotta love fluids! Hope this is helpful!

01-29-2003, 02:27 PM	#12
daveGT Registered Member Join Date: Mar 2001 Location: Sarcoxie, MO, USA Posts: 80	Ah, fluid dynamics. Fun stuff. Remember, you need to calculate the total head loss (THL) from a system in units of "feet." You gotta watch your units, and write out your entire energy conservation equation based on Bernoulli's equation to avoid unit problems. Been there, friend! Remember, the (2g) term is just a conversion term to convert your velocity, or kinetic head (v^2) to units of "feet." Likewise the pressure head (p) must be divided by gamma (density of the fluid) to get units of feet. The elevation, or potential head is already in units of feet. Your system losses, friction (hf) must also be in units of feet: hf = friction factor(length)(v^2) / (diameter)(2g) Everything can now be totaled. You're getting mixed up when you try to combine the flow rate (Q = v * A) with Bernoulli. Write out Bernoulli, sovle for the velocity at the open end of the pipe, then calculate flow (Q). Then you can convert your flow (Q) anything you want. Gotta love fluids! Hope this is helpful! __________________ '99 Cobra Red, stock so far, except for Steeda Tri-ax, Bassani X pipe, Recaro seats, and tint. '94 Lightning: White, stock except 50 series Flowmasters '99 GT (wife's): Chrome yellow, stock with some pretty slick "flame" pinstripes!