Vol 53, No 3-4 (2017)

Analysis of stressed state of torispherical and elliptical heads of pressure vessels having branch pipe on the head made it possible to disclose patterns of meridional and circumferential stress distribution in the heads under internal pressure, determine the area of maximum stresses, and ascertain the influence of nondimensional geometric parameters of vessels with heads with a branch pipe on the maximum compressive membrane circumferential stresses. The investigations were performed using finite-element method in a mixed variational formulation and a specially developed SAIS computer program.

The influence of various technical factors on the dynamics of compressive impregnation and on the filtration factor of polymeric binder into a powdery filler during molding of polymer composites was studied.

Results are presented for physical and mathematical modeling of the operation of different mixing chambers with a multiple jets inlet of a heat carrier in pneumatic conveying driers for potassium chloride. The influence of the shape of the chamber and the spacing of holes for heat carrier input on temperature inhomogeneity of the resulting mixture, particulates temperature and contact intensity of particulates with the chamber walls are considered. A mixing chamber design providing minimal contact intensity and sticking of the dryable particulates with the walls is recommended.

Hydrodynamic forces in slot seals of centrifugal pumps play a leading role in stabilization of vibrational activity of rotor pumps. It enables one to assess afresh the role of contactless seals of flow passages, such as bearing-seal assemblies of centrifugal pumps. The pump rotor adjusts automatically in symmetric slot seals under the action of hydrodynamic forces and moments. The proposed calculation procedure realizes a new design approach to creation of elements of flow passage of centrifugal pump having slot bearing-seal couples.

Results of an analysis of three types of gland seals with soft packing and inside seating of the pressure flange are presented. The packing had a cylindrical or trapezoidal cross section with standard or tapered o-ring gaskets. It was shown that gland seals with packing o-ring gaskets that were pressed beforehand in special matrices or directly in the gland body were most effective.

Universal relationships for boundary layer characteristics are used to derive an equation for the Nusselt number, which describes heat transfer in turbulent gas flows in straight and smooth channels. The equation contains the structural parameter that takes account of the influence of the variability of physical properties of the heat carrier on heat transfer. Analysis of quasi-thermal flow conditions showed that the derived equation agrees well with the Petukhov and Kirillov formula. The influence of the temperature factor T _w /T _av in the 0.2–5 variation range on heat transfer of the gas flows is analyzed. The results of calculations of heat transfer of air flow under conditions of variability of its physical properties are compared with theoretical and experimental data of other authors. It was found that, apart from the temperature factor, the Re number and atomicity of the gas affect the Nu/Nu₀ ratio (Nu₀ corresponds to constant properties). The nature of these influences differs for heating and cooling of the gas flow. For gases with atomicity higher than 8, heat transfer becomes self-similar with respect to the number of atoms in the gas molecule.

An approach for evaluating heat-exchanger operating efficiency using the calculated exergy efficiency (EE) that allows heat-exchanger system elements with low heat-transfer efficiency to be located and their maintenance (cleaning) to be managed according to their condition was proposed. Measurements required for the EE calculation were recorded automatically from the Automatic Process Control System databases of the application. Real-time mathematical modeling of the current mode of the facility using a computer training complex provided additional data.

The present work examines the hydrodynamic flow pattern in an industrial tubular baromembrane device on the example of commercially available membrane elements at pressures of 1.0–4.0 MPa. Experimental response curves and dependence curves of the longitudinal mixing coefficient were obtained as a function of the solution flow rate and the pressure in the membrane module. Based on this information, the criterial equation for calculating the longitudinal mixing coefficient was obtained. Numerical values of empirical coefficients are given, which can theoretically be used to calculate the longitudinal mixing coefficients as well as to predict the values for similar constructions of baromembrane systems operating at high transmembrane pressures.

This paper presents the results of experimental investigations of deceleration and entrainment OF water droplets moving in a counterflow of high-temperature combustion products of liquid fuels and flammable liquids. High-speed video cameras and panoramic optical methods (Particle Image Velocimetry, Stereoscopic Particle Image Velocimetry, Particle Tracking Velocimetry, Shadow Photography) were applied to record the parameters of movement and evaporation of water droplet flows. To generate the combustion products with a high controlled temperature (400–1900 K), some typical oils, gasoline, kerosene, acetone, and industrial ethanol were used. This paper generalizes the results of investigations by establishing for droplets and gases the ranges of Reynolds number variation within which complete droplet deceleration and removal by drift is possible.

A test method for investigating the heat-transfer coefficient as a function of the concentration of ice crystals in an ice slurry, the ice slurry flow rate in a tube, and the tube heat-flow density was presented. The experimental results were given. Comparative tests were carried out with a single-phase aqueous propylene glycol solution of the same initial density as the liquid from which the ice slurry was prepared.

Operating conditions of stationary rubber seals for sealing underwater oil production equipment as well as criteria and methods of ensuring working capacity of these seals at the design and numerical analysis stage are studied. Examples of the designed seals working in underwater oil production equipment are given.

The urgency of developing highly efficient dust collectors for fine dust was demonstrated. An experimental centrifugal-inertial dust collector was constructed. Experimental results showed that dust could be classified by fractions in the developed dust collector. The impacts on the biosphere and human health of fine dust in industrial wastes and air emissions were examined.

A technoeconomic analysis of the suitability of using suspended organic coal-water fuels (OCWF) of various component compositions was performed to determine the parameters that illustrate the priority of individual components and of the suspensions as a whole from the point of cost, ignition delay time, minimally adequate oxidizer temperature, combustion duration, and combustion heat of OCWF. The obtained data can be used to optimize the choice of the type and concentration of OCWF components that ensure efficient utilization of this type of fuel. An analysis was made of the feasibility of expanding the raw materials base for development of OCWF combustion technology.

The structures and properties of oil-tank sediments were investigated. It was shown that they could be used as a boiler-fuel component. A recycling method for oil-tank sediments was developed. An environmental and economic assessment of its implementation effectiveness was presented.