アポロ14号で熱流とコンベクションの実証実験を行った

P G Grodzka, T C Bannister

Science (New York, N.Y.)

|May 5, 1972

まとめ

微重力での実験では,液体やガスの熱流は主に導電によるものであることが明らかになった. 表面張力によって誘発されるコンベクションが発生し,他の未知のコンベクティブプロセスは熱伝達を強化します.

科学分野:

宇宙科学スペースサイエンス
流体力学流体力学
熱移転による熱移転です.

背景:

微重力での熱伝達の理解は,宇宙ミッションにとって極めて重要です.
以前の研究では,低重力環境では,限られたコンベクションが示唆されていた.

研究の目的:

微重力条件下で,ガスや液体の熱流と熱伝導を調査する.
宇宙実験からの流体行動と熱データを分析する.

主な方法:

アポロ14号の月面フライトバックミッションで実施された実験.
<10~6g環境での流量観測と熱データ収集を活用した.

主要な成果:

液体層における表面張力梯度によって引き起こされる観測された対流運動.
閉じられた液体やガスの熱流は,主に拡散式熱伝導によるものであることが確認されました.
解明されていないコンベクティブプロセスによる追加の熱伝送貢献を特定しました.

結論:

表面張力グラデーションは,微重力におけるコンベクションの重要な要因である.
拡散式熱伝導は,閉じた低重力流体における熱伝達の主要な方法である.
宇宙における追加のコンベクティブ熱伝達機構の完全な特徴を明らかにするために,さらなる研究が必要である.

さらに関連する動画

06:29

Simulation of Early Earth Hydrothermal Chimneys in a Thermal Gradient Environment

Published on: February 27, 2021

08:25

Measurements of Local Instantaneous Convective Heat Transfer in a Pipe - Single and Two-phase Flow

Published on: April 30, 2018

関連する概念動画

01:12

Heat Flow and Specific Heat

Heat is a type of energy transfer that is caused by a temperature difference, and it can change the temperature of an object. Since heat is a form of energy, its SI unit is the joule (J). Another common unit of energy often used for heat is the calorie (cal), which is defined as the energy needed to change the temperature of 1 g of water by 1 °C, specifically between 14.5 °C and 15.5 °C, since the energy needed shows a slight temperature dependence. Another commonly used unit is the kilocalorie...

01:14

Mechanisms of Heat Transfer I

Just as interesting as the effects of heat transfer on a system are the methods by which the heat transfer occur. Whenever there is a temperature difference, heat transfer occurs. It may occur rapidly, such as through a cooking pan, or slowly, such as through the walls of a picnic ice box. So many processes involve heat transfer that it is hard to imagine a situation where no heat transfer occurs. Yet, every heat transfer takes place by only three methods: conduction, convection, and radiation.

01:20

Conduction, Convection and Radiation: Problem Solving

There are three methods by which heat transfer can take place: conduction, convection, and radiation. Each method has unique and interesting characteristics, but all three have two things in common: they transfer heat solely because of a temperature difference; and the greater the temperature difference, the faster the heat transfer.
In order to solve a problem related to heat transfer, first of all, the situation needs to be examined to determine the type of heat transfer involved. This could...

01:20

Mechanisms of Heat Transfer II

In convection, thermal energy is carried by the large-scale flow of matter. Ocean currents and large-scale atmospheric circulation, which result from the buoyancy of warm air and water, transfer hot air from the tropics toward the poles and cold air from the poles toward the tropics. The Earth’s rotation interacts with those flows, causing the observed eastward flow of air in the temperate zones. Convection dominates heat transfer by air, and the amount of available space for the airflow...

01:23

The Joule and Joule–Thomson Experiments

Consider an adiabatic system composed of two chambers, A and B, designed such that no heat flows into or out of the system. Initially, chamber A is filled with a gas at a fixed temperature T1, pressure p1, and volume V1, while chamber B is evacuated. The gas is then gradually forced through a rigid, porous barrier to chamber B, ultimately reaching temperature T2, pressure p2, and volume V2. A piston on the right side maintains a constant pressure (p2), which is lower than p1. The significant...

01:14

Mechanisms of Heat Transfer

Heat transfer between the human body and its environment occurs through four main mechanisms: conduction, convection, radiation, and evaporation.
Conduction, accounting for approximately 3% of body heat loss at rest, is the process of exchanging heat between molecules of two materials in direct contact. This can result in both heat loss and gain. For instance, when the body is submerged in water, which conducts heat 20 times more effectively than air, it can either lose or gain significant heat.

関連する実験動画