KllrWolf
Electrical
- Mar 21, 2011
- 115
I am working with electric submersible motors filled with a mineral oil. The oil acts as both a cooling fluid and lubricant for the motor. The motors operate in sea water with a normal ambient rating of 30°C. The motor shell material thickness depends on the material being used, but is no more than .25" thick. The three main materials that we offer as normal options as a shell material are NiAlBronze, 316 Stainless Steel, or 6061-T6 Aluminum. Motors can range from 5 Hp to over 800 Hp in size.
My question is about doing the thermal calculations. For simplicity, we assume the surrounding water moves only due to natural convection, and the ocean is a large mass so the ambient never warms. Is it way off base to use the fact that the oil has the worst thermal transfer rate by far compared to either the metal shell or surrounding water, and therefore use the same heat transfer coefficient for a motor no matter the shell material? I do not need it to be spot on, but within about 3-4 degrees to pin down minimum dimensions for the motor.
My question is about doing the thermal calculations. For simplicity, we assume the surrounding water moves only due to natural convection, and the ocean is a large mass so the ambient never warms. Is it way off base to use the fact that the oil has the worst thermal transfer rate by far compared to either the metal shell or surrounding water, and therefore use the same heat transfer coefficient for a motor no matter the shell material? I do not need it to be spot on, but within about 3-4 degrees to pin down minimum dimensions for the motor.