Radiative-convective heat transfer in a system of two porous plates

Academic Science Complex, A. V. Lykov Institute of Heat and Mass Transfer, Academy of Sciences, Belorussia, Minsk. Translated from Inzhenerno-fizicheskii Zhurnal, Vol. 62, No. 1, pp. 95–101, January, 1992.     

Obtaining superadiabatic temperatures in combustion of gaseous fuel in a system of two porous plates with a periodic change of the direction of pumping

A mechanism of obtaining superadiabatic temperatures in a system of two porous plates is theoretically investigated. Data on the optimum pumping periods and on the value of the produced superadiabatic effect are presented.Academic Scientific Complex A. V. Luikov Institute of Heat and Mass Transfer of the Academy of Sciences of Belarus, Minsk. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 64, No. 5, pp. 569–576, May, 1993.     

Producing hydrogen from sodium borohydride using mesh nickel catalyst

In this study, nickel catalyst in the form of meshes was used in the stationary hydrogen generator with the circulation circuit of reactor to produce hydrogen from sodium borohydride. Based on the tests carried out, optimum parameters of the working process (working solution composition, temperature, pressure) have been determined on sodium borohydride with a capacity on hydrogen of up to 2 nm³/h.     

Coalescence and the initial stage of formation of nanofibers by the "vapor–liquid–solid" scheme

It has been shown that the diffusion interaction of growing impurity clusters within catalytic nanodroplets determines the important geometric parameters of a nanofiber. The characteristic time of coalescence of the clusters has been found.     

Two-dimensional modeling of filtration combustion in porous charges in a one-temperature approximation

Filtration combustion with a stationary front in porous charges is modeled within the framework of a one-temperature approximation. The results of numerical calculations are compared with an analytical evaluation for the quasi-one-dimensional case of a tube of variable cross section. Translated from Inzhenerno-Fizicheskii Zhurnal,-Vol. 71, No. 6, pp. 963–970, November–December, 1998.     

Experimental investigation of the kinetics of hydrolysis of sodium borohydride aqueous-alkaline solutions

Distinctive features of an experimental procedure for determination of the conversion of sodium borohydride in hydrolysis in an aqueous-alkaline medium are described; the procedure is based on measuring the amount of the released hydrogen. Technical and methodological features of implementation of this procedure and measurement errors are discussed; a technique for calculation of the conversion of sodium borohydride in hydrolysis is presented. Experimental data in the form of the constants of a quasistationary hydrolysis regime are given for different isothermal conditions. The range of experiments covers temperatures from 20 to 95°C and alkali concentrations from 10⁻² to 5 M.     

Long-term stability of sodium borohydrides for hydrogen generation

As a source of the high purity hydrogen, sodium and potassium borohydrides are investigated in terms of long-term stability in the form of the concentrated solutions, heterogeneous mixtures and in the solid state corresponding to NaBH₄ or KBH₄ crystal hydrates. In order to improve their stability during the long-term storage sodium and potassium hydroxides were added to the initial borohydride compositions. The effect of temperature, concentration of the borohydride and the alkaline solution, and the nature of the cation in the alkaline solution on the rate of borohydride hydrolysis was investigated. The differential technique developed for evaluation of the rate of borohydride hydrolysis was successfully applied for the determination of the long-term stability of the water-alkaline solutions containing NaBH₄(KBH₄)·5H₂O with 1–10 wt.% of NaOH or KOH at 30 °C and 50 °C.     

Focusing of shock waves on reflection from concave curvilinear surfaces

Results from a comparative analysis of experimental and numerical simulation of the processes of reflection of plane shock waves from concave axisymmetric and two-dimensional surfaces are presented.Academic Scientific Complex The A. V. Luikov Heat and Mass Transfer Institute, Academy of Sciences of Belarus, Minsk. Scientific-Industrial Company Prostor, Moscow Region, Krasnoarmeisk. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 65, No. 5, pp. 548–552, November, 1993.     

Conversion of methane to hydrogen in a reversible flow superadiabatic inert porous medium reactor

Using the analysis of the experimental data on partial oxidation of methane as an example, we have shown that the chemical processes in the inert medium of a reciprocating flow reactor can be modeled with good accuracy by the standard kinetic scheme for homogeneous processes due to the fact that the gas flow in the region of combustion is described by two temperatures — the gas and framework temperatures. Such a modification of the chemical model requires neither changing the recognized mechanism of homogeneous chemistry nor correcting the volume heat transfer coefficient.     

Hydrodynamic mechanism of absorption-wave propagation in a transparent liquid under the action of a laser pulse

The hydrodynamic approach is used to study the formation and movement of an absorption wave in water under the action of a pulse from a ruby laser.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 50, No. 4, pp. 570–576, April, 1986.