Mini-project : Oil Pipeline
In this problem you will analyze the heat transfer associated with an oil pipeline as it passes through a river. You may find it necessary to iterate your solution to find final values. When iterating, please make sure the temperatures used to evaluate fluid properties are converged to at least 3 significant figures.
For all other intermediate calculations, however, you should be using full precision in your answers. For all questions listed below please provide your final answers, that is after any necessary iteration of surface and/or fluid temperatures.
Oil flowing through a 12XS schedule pipe crosses through a river that is 10 m wide. This pipe has a 11.75 inch inner diameter, a 12.75 inch outer diameter, and is made of steel. Assuming the steel has a conductivity of 40 W/m-K,
The oil flows at an average velocity of 1.5 m/s through the pipe and is heated to reduce viscosity and related pumping losses. Assume the oil is 30 °C as the pipe enters the river. Oil properties may be approximated from Table A-13 in the textbook (also provided below).
During late Winter/early Spring as the Spring melt is just starting, this section of river can be quite icy and the average temperature is very close to (i.e. can be approximated as) 0 °C. The river water itself is flowing at 2 m/s over the pipeline.
Assume the pipe goes through the river far enough from the bottom and top surfaces such that any effects of the riverbed or water surface may be neglected.
12. What is the temperature change of the oil as it crosses through the icy river?
Temp. |
Density |
Specific |
Thermal |
Thermal |
Dynamic |
Kinematic |
Prandtl |
Vol. Exp. |
°C |
kg/m3 |
J/kg-K |
W/m-K |
m2/s |
kg/m-s |
m2/s |
[-] |
1/K |
0 |
899.0 |
1797 |
0.1469 |
9.097 x 10-8 |
3.814 |
4.242 x 10-3 |
46,636 |
0.00070 |
20 |
888.1 |
1881 |
0.1450 |
8.680 x 10-8 |
0.8374 |
9.429 x 10-4 |
10,863 |
0.00070 |
40 |
876.0 |
1964 |
0.1444 |
8.391 x 10-8 |
0.2177 |
2.485 x 10-4 |
2,962 |
0.00070 |
60 |
863.9 |
2048 |
0.1404 |
7.934 x 10-8 |
0.07399 |
8.565 x 10-5 |
1,080 |
0.00070 |
80 |
852.0 |
2132 |
0.1380 |
7.599 x 10-8 |
0.03232 |
3.794 x 10-5 |
499.3 |
0.00070 |
100 |
840.0 |
2220 |
0.1367 |
7.330 x 10-8 |
0.01718 |
2.046 x 10-5 |
279.1 |
0.00070 |
120 |
828.9 |
2308 |
0.1347 |
7.042 x 10-8 |
0.01029 |
1.241 x 10-5 |
176.3 |
0.00070 |
140 |
816.8 |
2395 |
0.1330 |
6.798 x 10-8 |
0.006558 |
8.029 x 10-6 |
118.1 |
0.00070 |
150 |
810.3 |
2441 |
0.1327 |
6.708 x 10-8 |
0.005344 |
6.595 x 10-6 |
98.31 |
0.00070 |
Table 1: Properties of oil. extract of table A-13 in Heat and Mass Transfer: Fundamentals and Applications by cengel and Ghajar