heat transfer calculation help..

[rickchentt]

Hello!
I am doing a research project on heat transfer from halogen lamp to the fully insulated asphalt sample (only surface is exposed to ambient air, now a copper tube is inserted 1" below the sample, will have ice water pump through cooper tube, and measure the water temperature at outlet to determine the energy generated.
Data:
Water properties at 25C
Cp=4.18 kJ/kg C
?=997.1 kg/ms3
?=0.8908*10-3
?=0.8933*10-6 m2/s
k=0.6076 W/m C
Pr=6.13
Copper tube dimension
Do=0.00635 m
Di=0.00435 m
A= 1.49*10-5 m2
L=0.15m
Flow rate Q= 3 ml/min
Temperature
Ti=0C
Tf=28C
Time=119mins.
heat flux from ashplat surface=1000W/m2
k of ashplat=5.38
What equation should i use to calculate the heat transfer to water raising from 0 to 28 C?
Should I use
Q=m*C*dT
Q=4.18*(3ml/min*119min)*28=41783J
or
Q=VA
Reynolds number
Re=16.55<2300 (Laminar flow)
Peclet number
Nusselt number (uniform duct temperature)
Nu=3.66
Heat transfer coefficient
511W/m2
Heat flux per unit area
Q=h(dt)= 14452W/m2
Power generated
H=14452* 1.49*10-5 m2=0.215W
Energy generated
Q=0.21w*(60*119min)=1535.1J
or?

Thank you for helping..

 

[rickchentt]

any help? please?

 

[vpl]

rickchentt,

research project? for school?



Patricia Lougheed

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[MortenA]

The energy transferred to the water is equal to dT*Cv*Q*den

where dT is temperature increase, Vc is mass heat capacity (of water), Q is the vol flow and den is the liquid density (of water). Check the units your self.

Best regards

Morten