Enhancement of refrigeration system performance by refrigerant capillary injection in evaporator

In this paper, the enhancement of refrigeration system performance by refrigerant capillary injection in evaporator was experimentally investigated. An experimental bench was developed in order to compare the performance of a refrigeration system operating in conventional throttling and capillary injection modes. The temperature distribution in the evaporator and the compressor electrical consumption were determined, showing that in the capillary injection mode, the refrigeration system was more stable, its time to reach the steady state was reduced by 62.5 % and its COP was enhanced by 9 %.

Improvement of the Process of Mechanical Dehydration of Five-Layer Wet Leather Semi-finished Products

To improve the process of mechanical dehydration of semi-finished wet leather products, a multilayer dehydration using felt materials – monshons was experimentally investigated. The process is conducted by vertical feed of semi-finished wet leather products on a base plate between rotating squeezing rollers. The D-optimal method of mathematical planning of the experiment and the Kano design matrix were used for conducting experiments. The multi-layer package consists of five layers of semi-finished wet leather products and two layers of moistureremoving materials between each layer, folded over the base plate. The studies were carried out in laboratory conditions on an experimental bench, taking into account the production parameters of processing. As a result of the study, mathematical dependences of the amount of removed moisture for each of five layers of semifinished wet leather product on the feed speed and the pressure of the squeezing rollers were derived. The analysis of the results showed that, with the existing parameters of mechanical dehydration, it was possible to simultaneously squeeze out moisture from five layers of the semi-finished leather product with a minimum pressure of the squeezing rollers and an average feed speed. The productivity of the technological process was more than five times higher in comparison with the productivity of similar roller machines. In the near future, this research methodology will be used to determine the technological factors affecting the extraction of excess moisture from a package consisting of ten semi-finished wet leather products and moisture-removing materials.

Spindle assembly with adjustable output characteristics

A method for controlling the output characteristics of spindle assemblies based on the use of tapered gas bearings with a small taper angle is proposed. An experimental bench for studying the performance characteristics of these bearings is described. The results of researches of gas-static bearings with a small taper angle are presented. Keywords: spindle assembly, gas-static support, small taper angle, experiment. [email protected]

Physical simulation of intra-arterial circulation using an experimental bench

The article describes the device and possibilities of application of the original device developed by us for simulation of intra-arterial circulation. The principles of operation of the device, a wide range of experimental and clinical studies in which it can be applied are outlined. The use of this useful model is illustrated by clinical examples.

Development and Realization of an Experimental Bench Test for Synchronized Small Angle Light Scattering and Biaxial Traction Analysis of Tissues

Insights into the mechanical and microstructural status of biological soft tissues are fundamental in analyzing diseases. Biaxial traction is the gold standard approach for mechanical characterization. The state of the art methods for microstructural assessment have different advantages and drawbacks. Small angle light scattering (SALS) represents a valuable low energy technique for soft tissue assessment. The objective of the current work was to develop a bench test integrating mechanical and microstructural characterization capabilities for tissue specimens. The setup’s principle is based on the integration of biaxial traction and SALS analysis. A dedicated control application was developed with the objective of managing the test procedure. The different components of the setup are described and discussed, both in terms of hardware and software. The realization of the system and the corresponding performances are then presented.

Numerical Modeling and Experimental Studies of the Operational Parameters of the Earth-To-Air Heat Exchanger of the Geothermal Ventilation System

This article is devoted to the analysis of the heat engineering characteristics of the operation of an Earth-to-Air Heat Exchanger, EAHE, with a circular cross-sectional shape, which is a component of the geothermal ventilation system. The authors analyzed literature sources devoted to the research of heat exchangers of the soil-air type of various designs and for working conditions in various soils. Much attention is paid to the issues of modeling the operation of such heat exchangers and the distinctive features of each of these models. Also important are the results of experimental studies carried out on our own experimental bench and with the help of which the numerical model was validated. The results of these studies are the basis for the development of a method for determining the optimal diameter of an EAHE under operating conditions for soil in Kyiv, Ukraine.