Home – Home – Jornals – Thermophysics and Aeromechanics 2005 number 1

The paper presents results of experimental study of aerodynamic characteristics of axisymmetric bodies with external mass injection and combustion. The flow structure was studied for bodies with separation zones on the nose and base parts of the body with different shapes. The influence of several parameters on supersonic flow was considered: freestream parameters, supply of inert or chemically reactive mass, physical and chemical parameters of fuel. The generalized relationships were developed for calculation of the nose and base drag that take into account the mass injection and combustion in supersonic flow.

The influence of eddy breakup devices (EBD) on characteristics of a turbulent boundary layer formed on an axisymmetric body of revolution in a nominally gradientless incompressible flow is experimentally studied. It is shown that the characteristics of the initial flow (without the EBD) do not contradict available physical concepts of the properties of a turbulent boundary layer formed on the body with lateral curvature. It is shown that the use of tandem positioning of EBDs in the boundary layer, which implies the use of two flat ring elements whose length is smaller than 75

Vortex dynamics and convective heat exchange at a turbulent unsteady flow around the heated-up cylinder in the unbounded flow and in a plane-parallel duct at a fixed Reynolds number 4.5(104 is computed on the basis of the solution of two-dimensional Reynolds and energy equations with the help of multiblock factored algorithm using the overlapping rectangular and cylindrical grids realized in the package VP2/3. Basing on a comparative analysis of the numerical predictions with the data of pressure and heat fluxes measurements as well as with computed results obtained on the basis of the FLUENT package, the Menter

Results of the numerical modelling of the heat island (heat spot) effect on the atmospheric boundary layer (ABL) structure are presented. Fully explicit algebraic models obtained with the aid of symbolic algebra from the transport equations for momentum and heat fluxes in the approximation of a weakly equilibrium turbulence are used to compute the turbulent momentum and heat fluxes. The three-parameter E -  ((²( model of thermally stratified turbulence is used to close the algebraic expressions for fluxes. The conducted two-dimensional computational test for the 24-hour ABL evolution shows that the mesoscale turbulence model of the third level of closure is capable of reproducing the most important structural ABL peculiarities over the underlying surface with a heat island, including those of them, which are inaccessible to the k -  -model of turbulence. The results obtained agree with measurement data and numerical results of other authors.

The gasdynamic structure of an over-expanded (n = 0.65) flat (sidewall ratio 3.5) supersonic (

Fluid dynamics and heat transfer in channels of a heat-exchanger-reactor formed by close parallel disks have been studied experimentally. The design provides a regular change in the air flow direction from center to periphery and vice versa. Measurements were carried out for a wide range of the Reynolds numbers for the slot width varying from 0.25 to 1.5 mm.

A computational technology is proposed for computation of the thermal state of a three-layer external walling with a transverse non-through insert (connector). The zones of the steel connector thermal influence are determined for various warmth-keeping jackets. The effect of ambient medium cyclical temperature on heat exchange characteristics is demonstrated.

Heating of a semitransparent gray medium with transparent and opaque boundaries effected by external, convective, and radiant fluxes was simulated numerically. Optimal values of convective and radiant parameters for uniform heating of a semitransparent sample were determined.

Here we present measurement results on the critical heat flux density and heat transfer at the flow of intensively evaporating and boiling films of liquid nitrogen on vertical uniformly heated surfaces together with results of high-speed visualization of the process. Measurements were carried out at the heated surfaces with the width of 67 mm and lengths of 20, 42, and 64 mm along the film flow over the range of inlet Reynolds numbers of 100

Isobaric heat capacity of aqueous lithium bromide solutions is studied experimentally in the temperature range from 0

Enthalpy of distilled gadolinium trifluoride GdF3 was measured in the solid and liquid states by the drop calorimeter method in the temperature range of 394(1675 K. Enthalpy changes in structure transformation (3.3?0.4 kJ/mole) and melting (54.2?0.4 kJ/mole) were determined. The high temperature limit of Debay temperature _D=520 K. was estimated. The heat capacity of GdF₃ was calculated for all phases. The original experimental values are presented.

The possibility of heat regeneration in the vortex-steam electric-arc plasmatorches is under discussion. A concept of regeneration degree is introduced for such devices. The efficiency growth versus heat regeneration completeness, thermal perfection of the plasmatorch, and steam enthalpy at the plasmatorch input are presented. Various ways of water supply into the auto-plasmatorch are considered. It is demonstrated that the incomplete heat regeneration should be applied when generating the high-enthalpy plasma. Experimental results obtained on the auto-plasmatorches designed by the author are presented. The paper is a summary of the works in this field.

In the present work, characteristics of a critical ejector with central primary-flow nozzle and convergent mixing chamber were examined. One-dimensional calculations show the influence of the secondary gas velocity on ejector parameters at an isobaric process of mixing in the chamber. An experimental ejector with a Mach 4.5 nozzle and a primary flow discharge pressure of p = 0.09 bar was found to start up at a pressure of 30 % in excess of the rated value. With design nozzle replaced with a geometrically similar smaller nozzle and with increased total pressure in the primary flow, the ejector starts up more readily and the ratio of mass rates of the flows increases. In experiments with an air ejector, a mass-rate ratio of 0.15 at a compression ratio of 10 was obtained.

Analysis was performed for aerodynamic characteristics of rotating cylinders in crossflow for the operating conditions of a windwheel with Magnus effect

February 20, 2005 marked the 80th anniversary of Prof. Eugenia M. Khabakhpasheva, Honored Scientist of Russia, Doctor of Technical Sciences. Her dedication to the cause and her zest for a creative approach to the solution of new problems are the key features in describing her walk in life.