PDF Publication Title:
Text from PDF Page: 038
2.2.2. Laws for viscosity and thermal conductivity Viscous effects in flows of dense gases have remained largely unexplored. One of the most important differences between dense gases and perfect gases is the downward curvature and nearly horizontal character of the isotherms in the neighborhood of the critical point and upper saturation curve in the p-v plane: the region of downward curvature of the isotherms is associated with the aforementioned reversed behavior of the sound speed in isentropic perturbations. In the same region, the specific heat at constant pressure, cp , can become quite large: this strongly influences the development of the thermal boundary layer and its coupling with the viscous boundary layer in high-speed flows. In the dense gas regime the dynamic viscosity μ and the thermal conductivity κ cannot be longer considered independent of the temperature and pressure, even in flows with relatively small temperature variations. On the other hand, the well-known Sutherland law, commonly used to represent viscosity variation with temperature, becomes invalid, as it is based on the hypothesis that the gas molecules act as non-interacting rigid spheres, and intermolecular forces are neglected. The complexity of the behavior of μ in the dense regime can be anticipated by recalling that the viscosity of liquids tends to decrease with increasing temperature, whereas that of gases tends to increase: the dense gas regime is a transition between these two qualitatively different behaviors. Similarly, the classical approximation of nearly constant Prandtl number ( Pr = μc p / k ≈ const ) cannot be used any more. As the thermal conductivity has roughly the same variation as viscosity with temperature and pressure, the behavior of Pr tends to be controlled by variations of cp. In regions where cp becomes large, strong variations of Pr can be observed, contrarily to what happens in perfect gases. Nevertheless, if the immediate vicinity of the thermodynamic critical point is excluded from considerations, the Prandtl number remains of order one, similar to perfect gases. In contrast, the Eckert number (Ec =U02 /(cpT0 ), where U0 and T0 refer to a suitable reference state) decreases significantly. Small flow Eckert number implies reduced sensitivity of the boundary layer to friction heating that remains negligible even at moderately large supersonic Mach numbers. Moreover, for flows past adiabatic walls the temperature, and thus also the density, is almost constant across the boundary layer. 37PDF Image | ANALYSIS AND OPTIMIZATION OF DENSE GAS FLOWS: APPLICATION TO ORGANIC RANKINE CYCLES TURBINES
PDF Search Title:
ANALYSIS AND OPTIMIZATION OF DENSE GAS FLOWS: APPLICATION TO ORGANIC RANKINE CYCLES TURBINESOriginal File Name Searched:
phd_thesis_PM_CONGEDO.pdfDIY PDF Search: Google It | Yahoo | Bing
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
IT XR Project Redstone NFT Available for Sale: NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Be part of the future with this NFT. Can be bought and sold but only one design NFT exists. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Turbine IT XR Project Redstone Design: NFT for sale... NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Includes all rights to this turbine design, including license for Fluid Handling Block I and II for the turbine assembly and housing. The NFT includes the blueprints (cad/cam), revenue streams, and all future development of the IT XR Project Redstone... More Info
Infinity Turbine ROT Radial Outflow Turbine 24 Design and Worldwide Rights: NFT for sale... NFT for the ROT 24 energy turbine. Be part of the future with this NFT. This design can be bought and sold but only one design NFT exists. You may manufacture the unit, or get the revenues from its sale from Infinity Turbine. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Supercritical CO2 10 Liter Extractor Design and Worldwide Rights: The Infinity Supercritical 10L CO2 extractor is for botanical oil extraction, which is rich in terpenes and can produce shelf ready full spectrum oil. With over 5 years of development, this industry leader mature extractor machine has been sold since 2015 and is part of many profitable businesses. The process can also be used for electrowinning, e-waste recycling, and lithium battery recycling, gold mining electronic wastes, precious metals. CO2 can also be used in a reverse fuel cell with nafion to make a gas-to-liquids fuel, such as methanol, ethanol and butanol or ethylene. Supercritical CO2 has also been used for treating nafion to make it more effective catalyst. This NFT is for the purchase of worldwide rights which includes the design. More Info
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
Infinity Turbine Products: Special for this month, any plans are $10,000 for complete Cad/Cam blueprints. License is for one build. Try before you buy a production license. May pay by Bitcoin or other Crypto. Products Page... More Info
| CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com | RSS | AMP |