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1.
A multi-dimensional mathematical thermal model of the oil-fired furnace has been developed. Radiation calculation of this
model is based on the Hottel's zone method incorporating with the statistical Monte Carlo method to determine the total exchange
areas. The whole furnace is divided into 4 gaseous zones and 18 surface zones. The Monte Carlo method integrated with the
least square smoothing technique considering both conservation and reciprocity is used to evaluate the total exchange areas,
i.e. surface–surface, surface–gas, gas–gas and gas–surface, directly for both the absorbing and emitting media. A better accuracy
is achieved in the determination of the total exchange areas by using the proposed smoothing Monte Carlo method.
Received on 10 April 2000 相似文献
2.
S. V. Demidkov 《Journal of Applied Mechanics and Technical Physics》1998,39(3):355-361
It is suggested that noncontact action of a magnetic field on shaped-charge jet elements be used to decrease the penetration
depth. A decrease in the depth is attained. A physicomathematical model for the process is constructed that allows one to
optimize performance of devices used to realize the action of an external magnetic field.
Lykov Academic Scientific Complex “Institute of Heat and Mass Exchange,” Minsk 220072. Translated from Prikladnaya Mekhanika
i Tekhnicheskaya Fizika, Vol. 39, No. 3, pp. 36–43, May–June, 1998. 相似文献
3.
In this paper, we will consider the modelling of problems in linear elasticity on thin plates by the models of Kirchhoff–Love
and Reissner–Mindlin. A fundamental investigation for the Kirchhoff plate goes back to Morgenstern (Arch. Ration. Mech. Anal.
4:145–152, 1959) and is based on the two-energies principle of Prager and Synge. This was half a century ago. 相似文献
4.
Vadim Travnikov 《Archive of Applied Mechanics (Ingenieur Archiv)》2010,80(2):103-122
A numerical investigation of the convective flow in the toroidal gap is presented. A new formulation of the incompressible
Navier–Stokes equation in terms of an auxiliary field that differs from the velocity by a gauge transformation [Weinen and
Liu in Commun Math Sci 1(2):317–332, 2003] has been used. The gauge freedom allows simple boundary conditions to be formulated
for the auxiliary field, as well as the gauge field. The gauge field eliminates the pressure distribution in the Navier–Stokes
equation. The influence of the geometric parameters and the Prandtl number is discussed. 相似文献
5.
The stability of a fluid-saturated horizontal rotating porous layer subjected to time-periodic temperature modulation is investigated
when the condition for the principle of exchange of stabilities is valid. The linear stability analysis is used to study the
effect of infinitesimal disturbances. A regular perturbation method based on small amplitude of applied temperature field
is used to compute the critical values of Darcy–Rayleigh number and wavenumber. The shift in critical Darcy–Rayleigh number
is calculated as a function of frequency of modulation, Taylor number, and Darcy–Prandtl number. It is established that the
convection can be advanced by the low frequency in-phase and lower-wall temperature modulation, where as delayed by the out-of-phase
modulation. The effect of Taylor number and Darcy–Prandtl number on the stability of the system is also discussed. We found
that by proper tuning of modulation frequency, Taylor number, and Darcy–Prandtl number it is possible to advance or delay
the onset of convection. 相似文献
6.
This paper presents isosteric-based adsorption equilibrium tests of three activated carbon samples with methanol as an adsorbate.
Experimental data was fitted into Langmuir equation, Freundlich equation and Dubinin-Astakov (D–A) equation, respectively.
The fitted adsorption equations were compared in terms of agreement with experimental data. Moreover, equation format’s impacts
on calculation of the coefficient of performance (COP) and refrigeration capacity of an adsorption refrigeration system was
analyzed. In addition, the sensitivity of each parameter in each adsorption equation format to the estimation of cycle’s COP
and refrigeration capacity was investigated. It was found that the D–A equation is the best form for presenting the adsorptive
property of a carbon-methanol working pair. The D–A equation is recommended for estimating thermal performance of an adsorption
refrigeration system because simulation results obtained using the D–A equation are less sensitive to errors of experimentally
determined D–A equation’s parameters. 相似文献
7.
R. S. Srivastava 《Shock Waves》2007,17(3):209-212
Lighthill (Proc. R. Soc. A 198, 454–470, 1949) considered the diffraction of a normal shock wave passing over a small bend. The bend being small Lighthill
was able to linearize the flow equations and solved the problem through several mathematical techniques. Following Lighthill
(Proc. R. Soc. A 198, 454–470, 1949), Srivastava and Chopra (J. Fluid Mech. 40, 821–831, 1970) extended the work to the diffraction of oblique shock waves. Srivastava (AIAAJ 33, 2230–2231, 1995) considered the problem of starting point of curvature and extended the work to yawed wedges (Srivastava
in Proceedings of the 14th International Mach reflection symposium Sun Marina Hotel, Yonezawa, Japan, 1–5 October 2000, pp.
225–249, 2002). Srivastava (Shock waves 13, 323–326, 2003) considered the problem for starting point of curvature when the relative outflow behind reflected shock before
diffraction has been subsonic and sonic. The present work is an extension of the work published in Srivastava (Shock waves
13, 323–326, 2003) when the wedge has been yawed through an angle. The results have been obtained for two angles χ = 60° and
χ = 40° (χ is the angle of yaw).
相似文献
8.
A. V. Demidov A. G. Makarov A. M. Stalevich 《Journal of Applied Mechanics and Technical Physics》2007,48(6):897-904
A mathematical model for the nonlinear hereditary viscoelasticity of polymer materials is proposed to predict deformation
processes of various complexity — from simple relaxation and simple creep to complex deformation-relaxation and reverse relaxation
processes with alternative loading and unloading.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 48, No. 6, pp. 147–157, November–December, 2007. 相似文献
9.
T. A. Bodnar’ 《Journal of Applied Mechanics and Technical Physics》2007,48(6):818-823
An approximate solution ω = A[ω, μ] of the nonlinear integral Nekrasov equation is obtained by successive replacement of the
kernel of the integral operator by a close one. The solution is sought not directly at the bifurcation point μ1 = 3 of the linearized equation ω = μL[ω] but at the point μ = 1 at which operator A[ω, μ], remaining nonlinear in ω, is linear
in μ.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 48, No. 6, pp. 50–56, November–December, 2007. 相似文献
10.
A transversely isotropic material in the sense of Green is considered. A complete solution in terms of retarded potential
functions for the wave equations in transversely isotropic media is presented. In this paper we reduce the number of potential
functions to only one, and we discuss the required conditions. As a special case, the torsionless and rotationally symmetric
configuration with respect to the axis of symmetry of the material is discussed. The limiting case of elastostatics is cited,
where the solution is reduced to the Lekhnitskii–Hu–Nowacki solution. The solution is simplified for the special case of isotropy.
In this way, a new series of potential functions (to the best knowledge of the author) for the elastodynamics problem of isotropic
materials is presented This solution is reduced to a special case of the Cauchy–Kovalevski–Somigliana solution, if the displacements
satisfy specific conditions. Finally, Boggio's Theorem is generalized for transversely isotropic media which may be of interest
to the reader beyond the present application.
Dedicated to Morton E. Gurtin 相似文献
11.
M. S. Soppa 《Journal of Applied Mechanics and Technical Physics》2008,49(4):642-645
A computer system of electromagnetic sounding data processing which allows the retrieval of the impedance distribution function
of a cylindrical surface is considered. Calculation results are presented.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 4, pp. 146–150, July–August, 2008. 相似文献
12.
Kh. M. Gamzaev 《Journal of Applied Mechanics and Technical Physics》2009,50(3):466-469
The spread of an oil slick in the sea is considered. A mathematical model of the process is proposed and a formulas for determining
the oil slick sizes in explicit form are obtained.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 50, No. 3, pp. 127–130, May–June, 2009. 相似文献
13.
14.
A computational thermo-metallographic and thermoelastoplastic model for the analysis of the quenching process is developed
and validated. The diffusive transfor-mations are modeled according to the Johnson–Mehl–Avrami–Kolmogorov model and the Scheil’s
additivity rule. Two different models are investigated for the non-diffusive transformation—the Koistinen–Marburger model
and the Yu model. A large displacement formulation is assumed for the deformation analysis, modeling the plastic behavior
of the material according to the Prandtl–Reuss model. Two different bilinear hardening models—the isotropic and the kinematic
hardening model—are used and compared. The model allows to evaluate the transient stress and strain distributions during the
quenching process, the final phases and hardness distributions, and to predict the residual stress and the final deformation
of the processed part. A good agreement between computational results and reference data is found 相似文献
15.
V. I. Melikhov O. I. Melikhov Yu. V. Parfenov S. E. Yakush 《Journal of Applied Mechanics and Technical Physics》2007,48(6):852-860
The temperature regime of a filtering unit being cooled after an accident at a nuclear power plant is considered. A mathematical
model is developed; the model is based on three-dimensional equations of thermohydrodynamics and takes into account heat-transfer
mechanisms (convection, heat conduction, and radiation). For the unit variants considered, the maximum value of temperature
in the sorbing module is less than 300°C, and the temperature reserve is 20–50°C.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 48, No. 6, pp. 92–102, November–December, 2007. 相似文献
16.
A numerical–analytic method for the identification of the axisymmetric mechanical shock load on a disk-shaped metal–piezoceramic
bimorph transducer is proposed. A problem is formulated based on the theory of thin two-layer plates. The solution is found
using the Laplace transform. By recovering the original function analytically, the problem is reduced to a system of Volterra
equations, solved numerically using Tikhonov’s regularization algorithm. The finite-element solution of the direct problem
is used as input data (potential difference between the electrodes of the piezoceramic layer). The results are analyzed 相似文献
17.
Quan Chen 《Rheologica Acta》2012,51(4):343-355
Cyclic block copolymer is a special type of block copolymer having no free ends. Comparison of the dynamic behavior between
cyclic and linear block copolymers enables an understanding of the role of chain ends in dynamics of the latter. In relation
to this point, analysis was made on the conformational dynamics for a cyclic bead-spring type diblock copolymer chain, AoB,
under the steady shear flow. Further comparison was made on the conformational behavior of the AoB chain and that of two symmetric
linear triblock copolymer chains, A–B–A and B–A–B. For these chains, the mobility was set to be higher for the A segments
than the B segments. Thus, for the AoB chain under the steady shear flow, the segments of the A block exhibit less orientational
anisotropy than those of the B block. This orientational contrast is enhanced for the A–B–A chain partly because the constraint
for the motion of the segments is less near the chain ends than near the chain center. Nevertheless, for the B–A–B chain,
the segmental orientation over the A block becomes more anisotropic than that over the B block. Detailed analysis shows that
this result is attributable to a high orientational correlation for the segments of two end B blocks, in particularly for
those near the block junctions. The correlated B segments exert a tensile force on the A block thereby significantly enhancing
the orientational anisotropy of the A segments. 相似文献
18.
19.
S. D. Shafrai T. N. Hatsevich 《Journal of Applied Mechanics and Technical Physics》1999,40(6):1148-1154
A brief comparative analysis of the various methods of evaluating the brittle fracture of metals is given. A plasticity index
for metals is proposed and substantiated, and the relation describing its effect on the relative contraction at rupture is
obtained.
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 40, No. 6, pp. 169–176, November–December, 1999. 相似文献
20.
L. E. Sternin 《Fluid Dynamics》2000,35(1):123-131
A comparative numerical analysis of the thrust characteristics of axisymmetric jet nozzles designed by various methods is
carried out. “Extremal“ nozzles designed by variational methods in the absence/presence of internal shocks (I), so-called
“truncated“ nozzles with a uniform characteristic (II), and nozzles designed by the method of conjugate circular arcs (III)
are considered. A comparison is carried out for both perfect and real gases (in the latter case the boundary layer gas viscosity
is taken into account). It is shown that extremal nozzles are the most efficient, while truncated nozzles are somewhat less
so. The thrust characteristics of nozzles designed by the method of conjugate circular arcs for both inviscid and viscous
flow are inferior to those of extremal nozzles by 0.7–1%.
Moscow, Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 152–162, January–February,
2000.
The research was carried out with financial support from the Russian Foundation for Basic Research (project No. 99-01-00891). 相似文献