Isentropic INDEX

Re), and the isentropic index or ratio of specific heats (7). The dependent group relates the mass of discharge to the valve size and to the reservoir conditions. It is suitable for assessing dynamical similarity under conditions of choked compressible flow. Substitution of PJRTq for Po in the dependent group produces a more conventional representation ... 

An ideal gas is completely defined by the gas constant (R) and isentropic index (7). For any such gas a critical flow factor (ij/) can be found assuming onedimensional isentropic mass flow (m ) through a minimum section or throat (A ) ... 

Given the isentropic index, y, the nozzle efficiency to the throat, riso, the overall nozzle efficiency, and the nozzle geometry to define A /A it is possible to solve the implicit equation (14.73) for the throat pressure ratio, Ptlp j, in terms of the exit pressure ratio, P /pqt- Figure 14.5 below shows the solution... 

If the working fluid is steam, check whether it is superheated or saturated at the first stage by comparing the inlet specific enthalpy, with the specific enthalpy of saturated steam appropriate to the inlet pressure, hg(po. ). If Aq.i dryness fraction and equation (15.112) to estimate the isentropic index, y. 

Equation 2.37 shows that the real work of detonation products is less than the potential energy of an explosive. The value of the work is related to the potential energy of an explosive, the expansion ratio of detonation products, and isentropic index k. 

When the explosion products expand unlimitedly V2 is unlimited), the work done by explosion products equals to the potential of an explosive. If the explosion heat is higher, the work is more. When the energy potential of an explosive and the expansion ratio are fixed, a larger isentropic index k means the more complete... 

Aleshin U. P., Arefieva L. H., Lugovtsev V. V, Speed of sound and isentropic index for Freon-12, -13, -12B1, -22, and ammonia.—In Thermodynamic Properties of the Most Important Working Substances for Refrigeration Equipment.—Tr. VNI (Kh), Moscow, 1976, p. 7—12. 

Evaluations of Rd and Y necessitate a knowledge of certain physical properties of the two liquids and the mixtures. The variation of refractive index with concentration is measured readily by refractometry, if I nT, — n21 is large. The coefficient of isothermal compressibility of a mixture t2 requires specialised equipment. Alternatively, it can be determined from the heat capacity and the coefficient of isentropic compressibility87, 88, the latter being yielded from velocity of sound data88. However, provided and 02 for the pure compounds are known, j312 is evaluated most conveniently on the basis of additivity, thus ... 

To give an idea of the pressure ratios involved, consider a diatomic gas such as nitrogen, where the specific-heat ratio, y = 1.4. For an isentropic expansion, the polytropic index is equal to the specific-heat ratio, and substituting n = y = 1.4 into equation... 

The gas flow through the control valve as a whole will be very close to adiabatic, and, as just noted, the expansion as far as the valve throat will incur only a small frictional loss, implying a process that is approximately isentropic. Accordingly we may substitute the ratio of the gas s specific heats, y = Cp/c,. for the polytropic index, n, in the flow equations (5.25) and (5.26) derived for an ideal nozzle in Chapter 5. Combining those two equations gives the mass flow, W, as ... 

The maximum flow is obtained for the reversible adiabatic, that is, isentropic state change. However, for the calculation of this process, the speed of sound has to be evaluated at the conditions in the cross-flow area (index 1) of the valve. For this purpose, an iterative procedure is necessary. The necessary steps are as follows ... 

Name (synonyms) Isobar molar heat capacity (300K) Isochor molar heat capacity (300K) Isentropic exponent (300K) Thermal conduct ivity (298K) Attraction constant Co-volume Critical pressure Critical tempera- ture Critical density Critical compress. factor Solubility water (0°C) Refractive index (589nm)... 

Given in paper [3.27] in graphical form are values [calculated by Eq. (3.7)] of the speed of sound and the adiabatic index (isentropic) kp for superheated vapors of Freon-22 at a pressure up to 6 MPa. Later, in the work of U. P. Aleshin and coworkers [0.1], diagrams of vv-T and kp -T for the same region of state were published. The calculations were carried out from an equation of state of type (0.7), where r = 9, 5, = 3, and 2, = 24. The equation was not tested, and the region of its applicability and composition of the initial experimental data were not specified. 

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