Temperature of fluid flowing through pipe

  • Thread starter Jay_
  • Start date
  • #176
So, the graph from the physicsforum page isn't useful unless I know the bhp at each rpm right? Because that is the only way I could calculate the flowrate.
No. From the engine specs, you know the horsepower at a specified RPM. You use this to find where your engine's curve should lie within the shaded area. Then, for that bhp, you know the heat load at all speeds. This inherently assumes that your car's curve really does lie within the shaded area.

Once you know the heat load at the specified engine speed and bhp, you can measure the temperature change at that engine speed and back out the coolant rate. That will give you the proportionality constant between the coolant rate and the engine speed.
  • #177
Hey Chet,

Let me know if the following is a correct way to go:

The graph in the other physicsforum thread gives me the decimal number to multiply with the horsepower right? Now I am using 2007 model, so that is 6th generation and this graph below gives me the horsepower with respect to rpm. But my engine size is bigger 3.5 L would it make a big difference?
http://home.comcast.net/%7Estevtecv6/dynos/NHT_30V6_HP_MD_j30eststock.jpg [Broken] (Link 1)

has the wheel horsepower I believe.

So the break horsepower would be 15% greater (or I might take 22% from the middle of 20-25% in the note below) from this link :

http://www.carthrottle.com/the-difference-between-bhp-and-whp-explained/ (Link 2)

I go to Link 1, but to convert the wheel horsepower to brake horsepower, I go to Link 2. I then multiply it by the corresponding number in the ordinate of the graph in the physicsforums thread.

Is that reasoning good?
Yes. I think that this makes sense to me. But please understand that, like yourself, this is also out of my range of experience. You really need to rely more on your own judgement at this point. If you still don't feel confident, you need to do some more background reading in an automotive engineering text. It's particularly important to understand what the various terms mean, e.g., brake hp.

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  • #178
Thanks Chet.
  • #179
Hi again Chet,

I have been successful in making equations for those graphs based on interpolations.

1.I get a wheel horsepower value for a given RPM, I multiply by 1.22 (because 22% is lost in going to the wheel, so I work backwards) and that gives me the brake horsepower at a given rpm. What is value of flow rate if the ordinate in that physicsforum link is say 0.8, what unit is it?

2.Also, do I have to multiply the value with 6 because it is given as flow rate/cyl? And I understand this is the volumetric flow rate I will have to multiply it by the density to get the mass flow?

Also I want to cite the book by Howarth (probably go through it a little bit), what is its name?