Page 25 - Entrophy Analysis in Thermal Engineering Systems

16 Entropy Analysis in Thermal Engineering Systems

or Davy’s work. They simply set to work to find out what heat is. They did not spec-
ulate on what it might be” [4].

2.3 Between 1800 and 1849

In the commencement of the 19th century, John Dalton noted the rise
of air temperature when it was compressed, and a drop of temperature when
the air was expanded. He communicated a series of 11 experiments to the
Society of Manchester on June 27, 1800 [7]. A year later, Dalton read four
papers before the same society. In the first paper, Dalton furnished the law of

mixed gases on the basis of the supposition that “The particles of one elastic fluid
may possess no repulsive or attractive power, or be perfectly inelastic with regard to the
particles of another: and consequently the mutual action of the fluids be subject to the
laws of inelastic bodies”; Ref. [8], p. 543.
According to Dalton’s law, the pressure of a gaseous mixture comprising
k nonreactive gases is equal to the sum of the partial pressures of the constit-
uent gases.

(2.3)
p mix ¼ p 1 + p 2 + … + p k
In the fourth paper, Dalton investigated the expansion of gases with the rise
of temperature. The subject was previously studied by not only Charles, as
mentioned in the preceding section, but also other French investigators like
Berthollet, Guyton de Morveau, and Duvernois, as stated by Dalton.
Through a series of experiments with air and some other gases, he was

led to ascertain that “all elastic fluids expand equally by heat—and that for any
given expansion of mercury, the corresponding expansion of air is proportionally some-
thing less, the higher the temperature”; Ref. [8], p. 600.
In a paper published in 1802, Joseph Gay-Lussac presented the results of
his research on expansion of gases and vapors along with an ample historical
sketch summarizing the efforts of earlier investigators of the subject, includ-
ing Amontons, Nuguet, Lahire, Stancari, Deluc, Roy, Saussure, Priestley,
Monge, Berthollet, Vandermonde, Guyton de Morveau, and Duvernois
[9]. Gay-Lussac found great discrepancies in the results of the previous
experimenters. He also acknowledged the (unpublished) findings of Charles:

“Although I had noticed a great many times that the gases oxygen, nitrogen, hydro-
gen, carbonic acid and atmospheric air expand to the same extent from 0° to 80°,
citizen Charles had, fifteen years before, discovered the same property in those gases;
but, never having published his results” [10].