How does the latent heat of steam change as operating pressure increases__________________?
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Answer: C. decreases
Explanation
As boiler operating pressure increases, the saturation temperature rises correspondingly. Higher saturation temperatures require less thermal energy to transform liquid water into steam. Therefore, the latent heat of vaporization decreases progressively at elevated pressures. Latent heat is the thermal energy absorbed during a phase change at constant temperature. Steam tables document thermodynamic properties showing this inverse relationship with pressure. At the critical point, the latent heat of vaporization drops entirely to zero.
Power plant engineers account for changing latent heat when designing high-pressure boilers. High-pressure steam cycles achieve greater thermodynamic efficiency despite lower latent heat. Boiler design must adjust heat transfer surface areas based on operating pressure parameters. Latent heat does not remain constant; it varies inversely with rising steam pressure. An increase in pressure causes the latent heat value to decrease, not increase. Thermodynamic phase change properties follow predictable physical laws without unpredictability.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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