[en] The isolation with ice plug of a high diameter horizontal pipeline section is a specific technique for repairs activities/ replacements of components owning to thermo-hydraulic installations working with liquid agents. The application of such technique don.t assumes stopping of the entire system. The ice plugging inside of the pipeline assumes using of a special device and of an own specific technology for application. The paper contains a brief description of the experimental technological facilities used, followed by setting off the main moments in evolution of two experimental tests carried out on the test section with 300 mm nominal diameter for demineralized water and, finally, by a brief results analysis and some conclusions. The paper is dedicated to the specialists working in the research and technological engineering. (authors)

[en] The result presented are refered to the development of a labyrinth-type model stage for the following parameters: delivery, 2x10^-3 m³/s; head, 3,2 kJ/kg. The design is based on its calculations by theoretical dependences in view of the modern investigation results of this type pump working processes. The characteristics obtained show the validity of the design concepts as well as a high efficiency and acceptable economic operation of the labyrinth-type pump units. The model stage can be used for developing pump units having heads and deliveries of 2-12 kJ/kg and 2-6x10^-3 m³/s, respectively with the efficiency not below 25 %

[en] The design described here means to produce a 'more satisfying instrument with less cost' than comparable instruments known up to now. Instead of one single turbine rotor, two similar ones but with opposite blade inclination and sense of rotation are to be used. A cylindrical measuring body is carrying in its axis two bearing blocks whose shape is offering little flow resistance. On the shaft, supported by them, the two rotors run in opposite direction a relatively small axial distance apart. The speed of each rotor is picked up as pulse recurrence frequency by a transmitter and fed to an electronic measuring unit. Measuring errors as they are caused for single rotors by turbulent flow, profile distortion of the velocity, or viscous flow are to be eliminated by means of the contrarotating turbines and the subsequently added electronic unit, because in these cases the adulterating increase of the angular velocity of one rotor is compensated by a corresponding deceleration of the other rotor. The mean value then indicated by the electronic unit has high accurancy of measurement. (RW)

[en] The problem of flow control of the heat carrier with a significant reduction of its temperature is studied. Several solutions to this problem are found taking into account the required amount of heat to the consumer. In this case, the heating supply object seems to be an equivalent heating device. An acceptable range of temperature reduction in the heat supply pipe is found, in which the problem of 100 % heat supply can be solved by increasing the flow of the heat carrier. It has been shown that this range can be significantly extended if there can be some decline in the quality of the heating supply – delivered volume of heat. The results can be used in the development of low-temperature heating modes – graphs of quantitative regulation of the heating supply. (paper)

[en] In this paper are defined fundamental principles for the ventilation of containment enclosures and gloveboxes, and examined criteria required to maintain containment in normal or accidental conditions. Dimensioning of ventilation network and associated equipment (adjustement and filtering devices). Some examples are given

No abstract available

[en] This study analyzes performance of the sherbet type ice making machine using seawater with respect to seawater volumetric flow rate, evaporation temperature, cooling water inlet and seawater inlet temperature as variables. Cooling water inlet and seawater inlet temperature are set considering average temperature of South Korea and the equator regions. Volumetric flow rate of seawater range is 0.75-1.75 LPM in this experiment. The results obtained from the experiment are as follows. As the seawater volumetric flow rate increases, or seawater inlet temperature increases, evaporation capacity tends to increase. At the point of seawater inlet temperature of 27°C and volumetric flow rate of 1.0LPM, evaporation capacity is over 2kW. On the other hand, results of COP change tendency are different from that of evaporation capacity. It appears to increase until volumetric flow rate of 1.0LPM, and decrease gradually from volumetric flow rate of 1.5LPM. This is due to the increase of compressor work to keep the evaporation pressure in accordance with the temperature of heat source. As the evaporation temperature decreases from -8 to -15°C, the evaporation capacity increases, but the COP decreases. (paper)

[en] Ultrasound stimulated microbubbles have been shown to be capable of breaking up blood clots through micro-scale interactions occurring near the clot surface. However, only a small fraction of bubbles circulating in the bloodstream will be in close proximity to such boundaries, where they must be to elicit therapeutic effects. Here, the accumulation and subsequent behavior of microbubbles displaced from an overlying flow channel to a boundary under radiation forces were examined. Experimental data were acquired using a novel high speed microscopy configuration and simulations were conducted to provide insight into the accumulation process. There was broad agreement between experiments and simulations, both indicating that the size distribution and number of bubbles arriving at the boundary depended on channel flow rate, applied pressure, and bubble concentration. For example, higher flow rates and lower pressures favored the accumulation of larger bubbles relative to the native agent distribution. Moreover, bubble dynamics were dependent on the surface type, exhibiting rapid translation along agarose gel surfaces whereas on fibrin surfaces, they accumulated in localized regions inducing repetitive strain cycles. The results indicate that the process of bringing bubbles from within a vessel to a boundary is complex and should be an important consideration in the development of therapeutic applications such as sonothrombolysis. (paper)

[en] Highlights: • Wet steam model was built for homogeneous condensation in ejector nozzle. • Effects of nozzle area ratio on condensation in nozzle were fully studied. • Influences of nozzle surface roughness on nozzle condensation were analyzed. - Abstract: Homogeneous condensation inside the ejector has been ignored by numerous researchers. In this paper, the wet steam model was utilized to study the influences of nozzle area ratio and surface roughness on homogeneous condensation in a primary nozzle. A substantial amount of latent heat is released during the homogeneous condensation process to increase static pressure and reduce Mach number. The increase of nozzle area ratio reduces condensation intensity and lowers nozzle pressure but increases liquid mass fraction. Furthermore, with the growth of surface roughness, the slightly increased dryness fraction is almost ineffective for alleviating erosion caused by tiny droplets; the slight decrease in mass flow rate will reduce ejector performance to some extent, while the sharp increase of entropy generation results in more energy wastes. Therefore, nozzle area ratio and surface roughness should be carefully designed to alleviate potential condensation and enhance ejector performance at the same time.

No abstract available