“Joule–Thomson effect”的概念、定义、翻译、参考文献-科学参考

Joule–Thomson effect

Physics

The change in temperature that occurs when a gas expands through a porous plug into a region of lower pressure. For most real gases the temperature falls under these circumstances as the gas has to do internal work in overcoming the intermolecular forces to enable the expansion to take place. This is a deviation from Joule’s law. There is usually also a deviation from Boyle’s law, which can cause either a rise or a fall in temperature since any increase in the product of pressure and volume is a measure of external work done. At a given pressure, there is a particular temperature, called the inversion temperature of the gas, at which the rise in temperature from the Boyle’s law deviation is balanced by the fall from the Joule’s law deviation. There is then no temperature change. Above the inversion temperature the gas is heated by expansion, below it, it is cooled. The effect was discovered by James Joule working in collaboration with William Thomson (later Lord Kelvin).

Chemistry

The change in temperature that occurs when a gas expands through a porous plug into a region of lower pressure. For most real gases the temperature falls under these circumstances as the gas has to do internal work in overcoming the intermolecular forces to enable the expansion to take place. This is a deviation from Joule’s law. There is usually also a deviation from Boyle’s law, which can cause either a rise or a fall in temperature since any increase in the product of pressure and volume is a measure of external work done. At a given pressure, there is a particular temperature, called the inversion temperature of the gas, at which the rise in temperature from the Boyle’s law deviation is balanced by the fall from the Joule’s law deviation. There is then no temperature change. Above the inversion temperature the gas is heated by expansion, and below it, it is cooled. The effect was discovered by James Prescott Joule working in collaboration with William Thomson (later Lord Kelvin) in 1852.

Chemical Engineering

The cooling that results when a highly compressed gas is allowed to expand adiabatically into a region of low pressure such that no work is done. The cooling effect occurs because as the molecules of the real gas separate during expansion, internal work is done in overcoming the attractive forces between them. A perfect gas, with no attractive forces between the molecules, shows no Joule–Thomson effect. The Joule–Thomson effect is more marked at lower temperatures and was used in the Linde process for the liquefaction of air. The phenomenon was discovered by James Joule working with William Thomson (later Lord Kelvin). Hydrogen is anomalous to the Joule–Thomson effect, by showing a rise in temperature at ambient temperature. This effect continues down to 193 K whereupon it cools under expansion. This is called the inversion temperature. Hydrogen was liquefied by Dewar in 1898, who cooled the gas below the inversion temperature by liquid air, and then used the principle of the Linde process. Helium, like hydrogen, is also anomalous, with an inversion temperature of 33 K.

单词	Joule–Thomson effect
释义	Joule–Thomson effect Physics The change in temperature that occurs when a gas expands through a porous plug into a region of lower pressure. For most real gases the temperature falls under these circumstances as the gas has to do internal work in overcoming the intermolecular forces to enable the expansion to take place. This is a deviation from Joule’s law. There is usually also a deviation from Boyle’s law, which can cause either a rise or a fall in temperature since any increase in the product of pressure and volume is a measure of external work done. At a given pressure, there is a particular temperature, called the inversion temperature of the gas, at which the rise in temperature from the Boyle’s law deviation is balanced by the fall from the Joule’s law deviation. There is then no temperature change. Above the inversion temperature the gas is heated by expansion, below it, it is cooled. The effect was discovered by James Joule working in collaboration with William Thomson (later Lord Kelvin). Chemistry The change in temperature that occurs when a gas expands through a porous plug into a region of lower pressure. For most real gases the temperature falls under these circumstances as the gas has to do internal work in overcoming the intermolecular forces to enable the expansion to take place. This is a deviation from Joule’s law. There is usually also a deviation from Boyle’s law, which can cause either a rise or a fall in temperature since any increase in the product of pressure and volume is a measure of external work done. At a given pressure, there is a particular temperature, called the inversion temperature of the gas, at which the rise in temperature from the Boyle’s law deviation is balanced by the fall from the Joule’s law deviation. There is then no temperature change. Above the inversion temperature the gas is heated by expansion, and below it, it is cooled. The effect was discovered by James Prescott Joule working in collaboration with William Thomson (later Lord Kelvin) in 1852. Chemical Engineering The cooling that results when a highly compressed gas is allowed to expand adiabatically into a region of low pressure such that no work is done. The cooling effect occurs because as the molecules of the real gas separate during expansion, internal work is done in overcoming the attractive forces between them. A perfect gas, with no attractive forces between the molecules, shows no Joule–Thomson effect. The Joule–Thomson effect is more marked at lower temperatures and was used in the Linde process for the liquefaction of air. The phenomenon was discovered by James Joule working with William Thomson (later Lord Kelvin). Hydrogen is anomalous to the Joule–Thomson effect, by showing a rise in temperature at ambient temperature. This effect continues down to 193 K whereupon it cools under expansion. This is called the inversion temperature. Hydrogen was liquefied by Dewar in 1898, who cooled the gas below the inversion temperature by liquid air, and then used the principle of the Linde process. Helium, like hydrogen, is also anomalous, with an inversion temperature of 33 K.
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