Apparatus and process for determining a convective heat transfer coefficient between a moving fluid and a bounding surface

An apparatus for experimentally determining a heat transfer coefficient comprising:

• a duct having a first fluid passage and a second fluid passage with a thin wall membrane separating the first fluid passage from the second fluid passage;
• a plurality of pedestals extending across the first fluid passage to support the thin wall membrane;
• a first fluid inlet and outlet for the first fluid passage;
• a second fluid inlet and outlet for the second fluid passage;
• a first temperature sensor at an inlet to the second fluid passage to measure a temperature of the second fluid at the inlet;
• a second temperature sensor at an outlet of the second fluid passage to measure a temperature of the second fluid at the outlet;
• a third temperature sensor to measure a temperature of the thin wall membrane;
• and,
• a computer to determine a heat transfer coefficient of an inner surface of the thin wall membrane based on a difference between the first and second temperature sensors and the temperature of the third sensor.

A process for experimentally determining a heat transfer coefficient of a surface comprising the steps of:

• forming a thin wall membrane with first surface and an opposed second surface with a heat transfer enhancement feature;
• passing a non-compressible fluid having a non-compressible fluid temperature along the first surface of the thin wall membrane such that a temperature of the thin wall membrane is substantially equal to the non-compressible fluid temperature;
• passing a compressible fluid along the second surface;
• measuring a temperature gain of the compressible fluid along the second surface;
• determining a temperature gain of the compressible fluid passing along the second surface from heat transfer resulting from the non-compressible fluid passing through the thin wall membrane;
• and,
• subtracting the heat transfer from the non-compressible fluid passing through the thin wall membrane from the temperature gain of the compressible fluid along the second surface to determine a heat transfer coefficient of the second surface with the heat transfer enhancement feature.