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Common density table
Published on:2015-2-6 16:32:43 Hits:

Common density table

Fluid has mass, mass volume unit called the density of the fluid inside to P said. Take any point in the fluid Eiichi small volume ^ V, fluid mass contained within the volume of ^ m, then almost all of its density P = ^ m / ^ V. Their density at any point, you can get by taking the limit:

1.gif  (1-11)

Inverse of density is called the hematocrit, using the symbol table wherein v is the volume occupied by the fluid mass units.

When the measured fluid is a liquid, if its components clear, and is commonly used medium, it can check its density taken from the relevant manuals. If the method is to use the measurement of the density requirements, the density values should be determined for each different temperature, if the temperature change is within ± 20 ℃, essentially linear relationship between density and temperature, and therefore can be measured at two different temperatures density values, linear relationship to the density and temperature, and then the density value is obtained on the medium at any point within this temperature range.

For gas, if the size of the molecule itself and the interaction force between molecules of gas meter, i.e., considered to be an ideal gas, then its density P, temperature T, pressure P represents the relationship between the state with the equation:

P = ^ (1-12)

Wherein, R is the gas constant, in units of J / kg. mol. K.

Because most of the measured gas mixed gas, the density of the gas to be analyzed later determined by the ratio of the gas composition. Various density of the gas composition is generally taken to be investigated by the manual. If already knowing the volume ratio of the various components, the density of the gas mixing ^ n can be calculated:

^ (1-13)

Wherein ^ ni-- i th gas component density in the standard state;

Xi-- is the volume ratio of the i-th gas component.

If the density is obtained under standard conditions ^ n, in the other state, i.e., the absolute temperature T, the density of the medium under the state of an absolute pressure P P obtained by the following formula:

 1.gif (1-14)

Where Tn. Absolute temperature Pn-- standard conditions (273.15K) absolute pressure (101 325.024Pa);

Kn, lower K-- standard Huai state and the general state of the compression factor, the lower the pressure, the range of the ideal gas is assumed that the establishment of the compression factor of 1.

Table 1-1 out of the compression factor Kn values of several common gas state under standard conditions.

1.gif


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