Dimensional analysis, conversion of units in an equation

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SUMMARY

The discussion centers on the dimensional analysis and unit conversion of the equation h=1147(1+0.05625T)(V^{0.6}/D^{0.4}) from units of kcal to Btu, and from Celsius to Fahrenheit. The correct conversion factors include 1 Btu = 0.252 kcal, 1 ft = 0.3048 m, and the temperature conversion for differences is 1 ºC = 1.8 ºF. The final transformed equation is h=2.479T(V^{0.6}/D^{0.4}), with the professor asserting the necessity of using the temperature difference conversion rather than the absolute temperature conversion.

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tkfn
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We are asked to transform this equation:

h=1147(1+0.05625T)\frac{V^{0.6}}{D^{0.4}}

where the units of each variable h, T, V and D are:

h->\frac{kcal}{h·m^{2}·ºC}
T->ºC
V->\frac{m}{s}
D->cm

into another equation where the units of each variable h, T, V and D now are:

h->\frac{Btu}{h·ft^{2}·ºF}
T->ºF
V->\frac{ft}{s}
D->inches

Data:
1 Btu <> 0.252 kcal
1 ft <> 0.3048m
1 ft <> 12 inches
1 ºC <> 1.8 ºF
(ºF) = 1.8(ºC)+32

The professor said the solution is

h=2.479T\frac{V^{0.6}}{D^{0.4}}

however I've tried the very same solution method which had worked for me in the past to solve other conversion problems but I can't seem to get the answer right, I'm confused as to which temperature conversion "factor" should we use, 1 ºC<>1.8 ºF or (ºF)=1.8(ºC)+32? I have really given up on this. :confused:
 
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Show your work.

In your unit conversions, you have something per degree C. You are not trying to find a particular temperature, so F = 1.8C + 32 is not the correct conversion.
 
Well what i did first is find out the units of the constant 1147 in the original equation so the principle of dimensional homogeneity at both sides of the = sign is satisfied:

\frac{kcal}{h·m^{2}·ºC}=\frac{kcal·cm^{0.4}·s^{0.6}}{h·m^{2.6}·ºC^{2}}·ºC·\frac{m^{0.6}}{cm^{0.4}·s^{0.6}}

Then I repeated the same process for the units of the new desired equation:

\frac{Btu}{h·ft^{2}·ºF}=\frac{Btu·inches^{0.4}·s^{0.6}}{h·ft^{2.6}·ºF^{2}}·ºF·\frac{ft^{0.6}}{inch^{0.4}·s^{0.6}}

Then I made an attempt to convert the constant with its units from the original equation into a constant with the units from the desired equation:

1147\frac{kcal·cm^{0.4}·s^{0.6}}{h·m^{2.6}·ºC^{2}}·\frac{Btu}{0.252kcal}·\frac{0.394^{0.4}inches^{0.4}}{cm^{0.4}}·\frac{0.3048^{2.6}m^{2.6}}{ft^{2.6}}· This is where I don't know how to proceed in order to convert the temperature units from ºC^{2} to ºF^{2}, the professor said we should use the factor 1ºC <> 1.8ºF when we have ΔT in an equation BUT when we have a specified T we should use (ºF)=1.8(ºC)+32, but SteamKing disagrees so I don't know how to proceed at all. I have a hunch my professor made a mistake but I'm not sure.
 

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