The Petrogenetic Model, an Extension of Bowen's Petrogenetic Grid

1962 ◽  
Vol 99 (6) ◽  
pp. 558-569 ◽  
Author(s):  
Peter J. Wyllie

AbstractBowen's petrogenetic grid is a PT projection containing univariant curves for decarbonation, dehydration, and solid-solid reactions, with vapour pressure (Pf) equal to total pressure (Ps). Analysis of experimental data in the system MgO–CO2–H2O leads to an expansion of this grid. Three of the important variables in metamorphism when Pf = Ps are P, T, and variation of the pore fluid composition between H2O and CO2. These can be illustrated in a three-dimensional petrogenetic model; one face is a PT plane for reactions occurring with pure H2O, and the opposite face is a similar plane for reactions with pure CO2; these are separated by an axis for pore fluid composition varying between H2O and CO2. Superposition of the PT faces of the model provides the petrogenetic grid. The reactions within the model are represented by divariant surfaces, which may meet along univariant lines. For dissociation reactions, the surfaces curve towards lower temperatures as the proportion of non-reacting volatile increases, and solid-solid reaction surfaces are parallel to the vapour composition axis and perpendicular to the PT axes. The relative temperatures of reactions and the lines of intersections of the surfaces can be illustrated in isobaric sections. Isobaric sections are used to illustrate reactions proceeding at constant pressure with (1) pore fluid composition remaining constant during the reaction, with temperature increasing (2) pore fluid composition changing during the reaction, with temperature increasing, and (3) pore fluid changing composition at constant temperature. The petrogenetic model provides a convenient framework for a wide range of experimental data.

Author(s):  
Adrian Briggs

This paper presents an overview of the use of low or mini-fin tubes for improving heat-transfer performance in shell-side condensers. The paper concentrates on, but is not limited to, the experimental and theoretical program in progress at Queen Mary, University of London. This work has so far resulted in an extensive data base of experimental data for condensation on single tubes, covering a wide range of tube geometries and fluid thermophysical properties and in the development of a simple to use model which predicts the majority of this data to within 20%. Work is progressing on the effects of vapor shear and on three-dimensional fin profiles; the later having shown the potential for even higher heat-transfer enhancement.


2014 ◽  
Vol 926-930 ◽  
pp. 1538-1541
Author(s):  
Hao Wang ◽  
Guo Quan Liu

Three-dimensional normal grain growth has been simulated in scale 300×300×300 using the generally accepted Potts model Monte Carlo method. The studies of the topology of grains indicate that the mean number of faces in the grain network <f>=13.91 is similar to other simulation results, but higher than most of the experimental data which containing a wide range of values, i.e., <f>=11.16~13.93. The three-dimensional AboavWeaire law and Liu-Yu law are observed to hold, but the fit coefficient is different from the theory models.


Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8080
Author(s):  
Iván Castro-Fernández ◽  
Ricardo Borobia-Moreno ◽  
Rauno Cavallaro ◽  
Gonzalo Sánchez-Arriaga

The validity of using a low-computational-cost model for the aerodynamic characterization of Airborne Wind Energy Systems was studied by benchmarking a three-dimensional Unsteady Panel Method (UnPaM) with experimental data from a flight test campaign of a two-line Rigid-Framed Delta kite. The latter, and a subsequent analysis of the experimental data, provided the evolution of the tether tensions, the full kinematic state of the kite (aerodynamic velocity and angular velocity vectors, among others), and its aerodynamic coefficients. The history of the kinematic state was used as input for UnPaM that provided a set of theoretical aerodynamic coefficients. Disparate conclusions were found when comparing the experimental and theoretical aerodynamic coefficients. For a wide range of angles of attack and sideslip angles, the agreement in the lift and lateral force coefficients was good and moderate, respectively, considering UnPaM is a potential flow tool. As expected, UnPaM predicts a much lower drag because it ignores viscous effects. The comparison of the aerodynamic torque coefficients is more delicate due to uncertainties on the experimental data. Besides fully non-stationary simulations, the lift coefficient was also studied with UnPaM by assuming quasi-steady and steady conditions. It was found that for a typical figure-of-eight trajectory there are no significant differences between unsteady and quasi-steady approaches allowing for fast simulations.


1996 ◽  
Vol 118 (1) ◽  
pp. 11-19 ◽  
Author(s):  
D. Bohn ◽  
R. Emunds ◽  
V. Gorzelitz ◽  
U. Kru¨ger

Increasing the thermal efficiency by higher turbine inlet temperatures is one of the most important aims in the area of gas turbine development. Because of the high temperatures, the turbine vanes and blades have to be cooled, and also knowledge of the mechanically and thermally stressed parts in the hottest zones of the rotor is of great interest. The prediction of the temperature distribution in a gas turbine rotor containing closed, gas-filled cavities, for example, in between two disks, has to account for the heat transfer conditions encountered in these cavities. In an entirely closed annulus, forced convection is not present, but a strong natural convection flow exists, induced by a nonuniform density distribution in the centrifugal force field. In Bohn et al. (1994), experimental and numerical investigations on rotating cavities with pure centripetal heat flux had been carried out. The present paper deals with investigations on a pure axially directed heat flux. An experimental setup was designed to realize a wide range of Ra numbers (2·108< Ra < 5·1010) usually encountered in cavities of gas turbine rotors. Parallel to the experiments, numerical calculations have been conducted. The numerical results are compared with the experimental data. The numerical scheme is also used to account for the influence of Re on heat transfer without changing Ra. This influence could not be pointed out by experiments, because a variation of the Re–Ra characteristic of the employed annuli was not possible. It was found that the numerical and experimental data are in quite good agreement, with exception of high Ra, where the numerical scheme predicts higher heat transfer than the experiments show. One reason may be that in the experiments the inner and outer cylindrical walls were not really adiabatic, an assumption used in the numerical procedure. Moreover, the assumption of a two-dimensional flow pattern may become invalid for high Ra. The influence of three-dimensional effects was studied with the three-dimensional version of the numerical code. In contrast to the radial directed heat transfer, it was found that Nu is much smaller and depends strongly on Re, whereas the radial heat transfer is only weakly influenced by Re.


2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Konrad Kacprzak ◽  
Krzysztof Sobczak

AbstractAn influence of the overlap on the performance of the Classical Savonius wind turbine was investigated. Unsteady two-dimensional numerical simulations were carried out for a wide range of overlap ratios. For selected configurations computation quality was verified by comparison with three-dimensional simulations and the wind tunnel experimental data available in literature. A satisfactory agreement was achieved. Power characteristics were determined for all the investigated overlap ratios for selected tip speed ratios. Obtained results indicate that the maximum device performance is achieved for the buckets overlap ratio close to 0.


2011 ◽  
Vol 105 (4) ◽  
pp. 1633-1641 ◽  
Author(s):  
Xiao Hu ◽  
Wendy M. Murray ◽  
Eric J. Perreault

The mechanical properties of the human arm are regulated to maintain stability across many tasks. The static mechanics of the arm can be characterized by estimates of endpoint stiffness, considered especially relevant for the maintenance of posture. At a fixed posture, endpoint stiffness can be regulated by changes in muscle activation, but which activation-dependent muscle properties contribute to this global measure of limb mechanics remains unclear. We evaluated the role of muscle properties in the regulation of endpoint stiffness by incorporating scalable models of muscle stiffness into a three-dimensional musculoskeletal model of the human arm. Two classes of muscle models were tested: one characterizing short-range stiffness and two estimating stiffness from the slope of the force-length curve. All models were compared with previously collected experimental data describing how endpoint stiffness varies with changes in voluntary force. Importantly, muscle properties were not fit to the experimental data but scaled only by the geometry of individual muscles in the model. We found that force-dependent variations in endpoint stiffness were accurately described by the short-range stiffness of active arm muscles. Over the wide range of evaluated arm postures and voluntary forces, the musculoskeletal model incorporating short-range stiffness accounted for 98 ± 2, 91 ± 4, and 82 ± 12% of the variance in stiffness orientation, shape, and area, respectively, across all simulated subjects. In contrast, estimates based on muscle force-length curves were less accurate in all measures, especially stiffness area. These results suggest that muscle short-range stiffness is a major contributor to endpoint stiffness of the human arm. Furthermore, the developed model provides an important tool for assessing how the nervous system may regulate endpoint stiffness via changes in muscle activation.


2017 ◽  
Vol 21 (4) ◽  
pp. 342-362 ◽  
Author(s):  
Natalie Ishmael ◽  
Anura Fernando ◽  
Sonja Andrew ◽  
Lindsey Waterton Taylor

Purpose This paper aims to provide an overview of the current manufacturing methods for three-dimensional textile preforms while providing experimental data on the emerging techniques of combining yarn interlocking with yarn interlooping. Design/methodology/approach The paper describes the key textile technologies used for composite manufacture: braiding, weaving and knitting. The various textile preforming methods are suited to different applications; their capabilities and end performance characteristics are analysed. Findings Such preforms are used in composites in a wide range of industries, from aerospace to medical and automotive to civil engineering. The paper highlights how the use of knitting technology for preform manufacture has gained wider acceptance due to its flexibility in design and shaping capabilities. The tensile properties of glass fibre knit structures containing inlay yarns interlocked between knitted loops are given, highlighting the importance of reinforcement yarns. Originality/value The future trends of reinforcement yarns in knitted structures for improved tensile properties are discussed, with initial experimental data.


1985 ◽  
Vol 29 (01) ◽  
pp. 23-38
Author(s):  
Okitsugu Furuya ◽  
Shin Maekawa

In order to develop an analytical tool for predicting the off-design performance of supercavitating propellers over a wide range of operating conditions, a lifting-line theory was combined with a two-dimensional supercavitating cascade theory. The results of this simple method provided fairly accurate predictions for the performance at fully developed cavitating conditions. It was indicative that the fully developed supercavitating (s/c) propellers had strong cascade effects on their performance, and also that the three-dimensional propeller geometry corrections could properly be made by the lifting-line theory. However, the predicted performance with this propeller theory showed a significant deviation from experimental data in the range of J's larger than Jdesign, where partially cavitating conditions are expected to occur. Effort was then made on improving the prediction capability of the above propeller theory at partially cavitating (p/c) conditions. A new nonlinear partially cavitating cascade theory was then developed to provide a proper 2-D loading basis under such conditions. Two-dimensional cascade experiments were then conducted to prove the accuracy of the p/c and s/c cascade theories. The measured forces and flow observations obtained in these experiments shed a new light on the relationship between the forces and cavitation numbers at small angles of incidence. Corrected lift and drag forces were then used in the propeller program. The calculated results for KT and KQ with the new force data successfully correlated with the experimental data, now covering a large J-range where the partially cavitating conditions exist.


Author(s):  
Roque Corral ◽  
Fernando Gisbert

A correlation-based transition model has been introduced in a RANS solver to improve the prediction of the transition from laminar to turbulent flow regime in low-pressure turbine blades. The model has been validated by comparing the numerical results against experimental data. The transition model correctly predicts the transition process due to the separation of the laminar boundary layer in a wide range of situations, ranging from steady two-dimensional simulations to unsteady multirow three-dimensional simulations with cavities, improving in all cases the sensitivity of the RANS solver to variations in the Reynolds number.


Author(s):  
N. S. Aryaeva ◽  
E. V. Koptev-Dvornikov ◽  
D. A. Bychkov

A system of equations of thermobarometer for magnetite-silicate melt equilibrium was obtained by method of multidimensional statistics of 93 experimental data of a magnetite solubility in basaltic melts. Equations reproduce experimental data in a wide range of basalt compositions, temperatures and pressures with small errors. Verification of thermobarometers showed the maximum error in liquidus temperature reproducing does not exceed ±7 °C. The level of cumulative magnetite appearance in the vertical structure of Tsypringa, Kivakka, Burakovsky intrusions predicted with errors from ±10 to ±50 m.


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