Geometry
A mixing duct is a common device used to mix separate flows. Commonly used in chemical processing and refineries. In certain cases one may desire to mix flows with different temperatures, one hot and cold.
Here there are two different flows:
1) Hot air at 500 deg C (773K) at 5 m/s
2) Cold air at 50 deg C (323K) at 5 m/s
Constraints:
1) Achieve a mixed air at output with maximum 10% variation in its temperature.
2) Minimize pressure drop, target is to be below 4 in water (1 kPa ) from inlet to exit.
Control Case: Temperature (in K) and Pressure Drop (Pa)
Temperature variation: 100 % Pressure drop: 230 Pa
Final Mixer Design (Trial 8)
Temperature variation: 4 % Pressure drop: 907 Pa
Theoretical mixed temperature matches the theory :
Design became simpler than I had expected in this case. But it was not always like this...
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Trial 2: Used cylinders to enhance mixing, didn't do much but increase pressure drop
Temperature variation: 92 % Pressure drop: 278 Pa
Trial 4: Baffles
Trial 4: Baffles
Temperature variation: 14 % Pressure drop: 1518 Pa
Temperature variation: 14 % Pressure drop: 1518 Pa
Trial 7: Design refinement
Temperature variation: 4 % Pressure drop: 1931 Pa