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Zorluk: KolayHeat Transfer: Conduction

A technician is designing a solid metal firewall to separate a hot engine compartment from a passenger cabin. Which of the following modifications will specifically reduce the rate of heat transferred by conduction through the solid wall?

  1. Increasing the overall thickness of the solid metal wall.Cevap
  2. B
    Using a metal alloy that has a higher thermal conductivity.
  3. C
    Polishing the engine-facing surface to a shiny, reflective finish.
  4. D
    Cutting open vents into the wall to allow air circulation.

Cevap

Increasing the overall thickness of the solid metal wall.
Heat conduction through a solid occurs as energetic molecules transfer kinetic energy to neighboring molecules. By increasing the thickness of the wall, the heat has to travel a greater physical distance. This decreases the temperature gradient across the material, which proportionally slows down the rate of conductive heat transfer.

Adım Adım Çözüm

1
Identify the mode of heat transfer being tested.
The question specifically asks about conduction, which is the transfer of heat through direct contact within a solid material.
Different modifications affect different modes of heat transfer (conduction, convection, and radiation).
2
Evaluate how physical changes affect conduction.
Conduction rate is reduced by increasing the distance the heat must travel (thickness) or by using a material with lower thermal conductivity.
The rate of thermal conduction is inversely proportional to the thickness of the material.
3
Analyze the given options against conduction principles.
Increasing thickness reduces conduction. Reflective surfaces affect radiation. Vents introduce convection. Higher conductivity increases conduction.
This confirms that only increasing the thickness specifically addresses and reduces conduction.

Anahtar Kavram

Factors Affecting Thermal Conduction
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Konular

Heat Transfer: Conduction

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