Heat Transfer Rate & Estimation in Air-Steam Flow System

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SUMMARY

The discussion focuses on estimating the heat transfer rate in an air-steam flow system involving a copper tube heated by condensing steam. Key tasks include determining the heat transfer rate at three air flow rates (10, 20, and 30 from a rotameter), calculating the overall heat transfer coefficient, estimating the inside air film heat transfer coefficient, and predicting it using the Dittus-Boelter equations. Participants are encouraged to develop an energy balance for the system and consider heat exchanger theory for a comprehensive understanding of the heat transfer dynamics.

PREREQUISITES
  • Understanding of heat exchanger theory
  • Familiarity with Dittus-Boelter equation for heat transfer coefficient calculations
  • Knowledge of fluid dynamics, particularly in air-steam systems
  • Basic principles of thermodynamics and energy balance
NEXT STEPS
  • Research the Dittus-Boelter equation for predicting film heat transfer coefficients
  • Study experimental methods for measuring heat transfer coefficients in heat exchangers
  • Explore energy balance calculations in thermal systems
  • Investigate the impact of flow rates on heat transfer efficiency in air-steam systems
USEFUL FOR

Engineers, thermal system designers, and researchers interested in heat transfer analysis, particularly in air-steam flow systems and heat exchanger applications.

dj_silver
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Thought this would be the most appropriate forum to ask for help

Air flows through a copper inside tube and is heated by saturated steam condensing on the outside of the tube.

1. Determine the rate of heat transfer to the air at 3 different flow rates of the air (rotameter readings 10, 20 and 30).
For each air flow rate:
2. Experimentally determine the overall heat transfer coefficient based on the outside area of the pipe.
3. Estimate the inside (air) film heat transfer coefficient assuming that the resistances of the copper wall and steam film are small compared to the resistance of the air film.
4. Predict the film heat transfer coefficient using the Dittus-Boelter equations.
5. Compare the film heat transfer coefficients from the experiments with those calculated from the Dittus-Boelter equation. Comment on the comparison.
6. Estimate the steam consumption, stating assumptions.

The schematic is attached.

The dimensions of central copper tube are:
Length: L = 300 mm
Inside diameter: di = 4.5 mm
Outside diameter: do = 6.3 mm

Just wondering what the best way to approach this is, and how to answer all the questions, what measurements to make etc?

Any links or straight out advice?

Thanks very much
 

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Develop the energy balance for the system. What comes in is what goes out in some form or another. Ask yourself what those different ways energy can be manifested. I would suggest to look at simple heat exchanger theory for hints since that's what this is.
 

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