Papers by Keyword: Pressure

Abstract: The uncontrollable forming quality of component caused by the uncontrollable expansion pressure of silicon rubber mandrel has long been an unsolved problem in the fabrication of composite hat-shaped components. Here,we advanced a novel mandrel pressurization method combining silicon rubber mandrel and inflatable mold. Cure experiments were carried out based on the combined mandrel with different adjustable apertures. At the same time, the resin pressure of the components was monitored on-line during the curing process by using a self-built pressure on-line monitoring system, and their geometric accuracies and forming quality were evaluated. The experimental results show that the combined mandrel forming method can control the uniformity of pressure, geometric accuracies and forming quality of the hat-shaped component effectively, and the optimal size range is obtained with the hole ratio of 0.4~0.53. Compared with the traditional auxiliary forming method, combined mandrel pressurization method greatly reduces the requirements on the size of the mandrel structure and broadens the process window of the mandrel for the curing of hat-shaped component.

Abstract: The aim of the paper is to evaluate numerical analysis of the fluid flow during the outflow from vessel orifices at various locations. The problems of the outflow velocities and pressure fields were well-chosen for the given purposes. The selected fluid flow problems were solved by numerical simulation using FEM in ANSYS. For numerical simulation, we used the basic steps to design an abstract model in the ANSYS virtual environment. Numerical simulation requires a geometric model complemented by physical properties of flowing fluids as well as both the initial and boundary conditions. It is then possible to calculate the velocity and pressure fields by numerical simulation for a particular fluid type. The results obtained from the numerical simulation were compared with those of the analytical solution. The results obtained from modeling and numerical simulation correspond to the actual values ​​with minimum deviations. The demonstrated type of the problem solved by numerical simulation and modeling confirmed the advantages and possibilities of flexible solutions for any combination of problems in the field of ​​fluid dynamics. Modeling and numerical simulation of fluid flow can provide results regarding the speed and the pressure fields in vessels and pipelines.

Abstract: The article is devoted to the research into the utilization of large volume industrial wastes to produce mineral-polymer composite construction materials. To produce the composites, polyvinyl chloride wastes have been suggested as binding thermoplastic matrix and ash-and-slag wastes, which are the by-product of coal combustion at TPP of Irkutsk Oblast, as mineral filler. Since the problem of accumulation and storage, such as large volumes of power generation industry wastes is becoming more and more serious, the recycling of these wastes with the production of useful products is the vital task. Plants that manufacture products from PVC also produce plastic wastes in the form of rejected and substandard raw material, which can be recycled. At the same time, the problem of production available construction materials for the Baikal region from the local cheap raw material is solved. The team of Irkutsk National Research Technical University has conducted a number of the industrial trials on the production of mineral-polymer composites by the method of extrusion. As a result, the principal opportunity of co-utilization of PVC wastes and ash-and-slag materials during the production of composite construction materials has been testified. Local construction companies can use the produced materials.

Abstract: We present transport and thermodynamic properties of CeRu₂Al₁₀ controlled by pressure in a vicinity of a critical pressure P_C ~ 4GPa, where antiferromagnetic ordering disappears. The resistivity under pressure was measured with DC four terminal method and the AC specific heat under pressure was measured by Joule heating type technique. The pressure was applied by cubic-anvil-apparatus and palm-cubic-anvil-apparatus. The results of AC specific heat indicate T_N holds at high temperature up to 3.9 GPa but suddenly disappears above this pressure. We confirmed T_N from thermodynamic properties. Although CeRu₂Al₁₀ is in a Kondo semiconducting ground state at 4 GPa, temperature dependences of electrical resistivity at 4.6 GPa and 5.9 GPa indicate metallic ground state in these pressures. CeRu₂Al₁₀ does not show superconductivity down to 0.7 K at 4.6 GPa and 5.9 GPa.

Abstract: Four different riser pipe exit configurations were modelled and the flow across them analysed using STAR CCM+ CFD codes. The analysis was limited to exit configurations because of the length to diameter ratio of riser pipes and the limitations of CFD codes available. Two phase flow analysis of the flow through each of the exit configurations was attempted. The various parameters required for detailed study of the flow were computed. The maximum velocity within the pipe in a two phase flow were determined to 3.42 m/s for an 8 (eight) inch riser pipe. After thorough analysis of the two phase flow regime in each of the individual exit configurations, the third and the fourth exit configurations were seen to have flow properties that ensures easy flow within the production system as well as ensure lower computational cost. Convergence (Iterations), total pressure, static pressure, velocity and pressure drop were used as criteria matrix for selecting ideal riser exit geometry, and the third exit geometry was adjudged the ideal exit geometry of all the geometries. The flow in the third riser exit configuration was modelled as a two phase flow. From the results of the two phase flow analysis, it was concluded that the third riser configuration be used in industrial applications to ensure free flow of crude oil and gas from the oil well during oil production.

Abstract: The treatment of aortic aneurysm varies according to each patient. Stent implantation is one of many methods used to stabilize diseases. The information obtained from hemodynamic parameters in the pathological aorta with stent could help doctors in choosing the treatment before the surgery. In this context, the numerical simulation of fluid dynamics is an essential tool that can give us more detailed information that could be exploited by surgeons to find appropriate solutions to some pathologies. In this work, a study of two models of aortas: with and without stent was presented. A comparison of the results of changes in pressures and shear stresses of aortas in systolic and diastolic phases was discussed. The obtained results show a nearly similar tendency of variation for both models, which justifies the effectiveness of the type of stent chosen and its effect on the improvement of the blood flow. The methodology used in this work has revealed the detailed and necessary information for both cases studied and has shown the interest of the numerical tools for diagnosis and surgery.

Abstract: For the first time the influence of pressure of chitosan solutions in carbonic acid on the adsorption of chitosan onto a collagen tissue of biological heart-valve prostheses and on the structure of the resulting biocomposite was studied. It turned out that the dependence of an amount of the chitosan adsorbed onto the collagen tissue has bell-shaped form reaching a maximum adsorption of about 0.8 weight. % at 30-40 MPa and then falling to 0.3 wt. % with further pressure increase up to 50 MPa. It was found that this treatment leads to a significant change of the morphology of the tissue surface which depends on the pressure in the system. It was also revealed that under pressure growth collagen fibrils are compacted in the tissue bulk which leads to the extrusion of the polymer embedded in the collagen matrix.

Abstract: The paper presents the results of the researches on structure modifications of the surface of iron-ore hematite concentrate under the pressure up to 20000 MPa with the use of modern research method – scanning electron microscopy. Hematite iron-ore concentrate (hematite) is the filling for the newest composite material which can be used in the domain of nuclear building. Such composite material has the same aluminum containing matrix in its base and it contains significant amount of such filling. This modern composite material can be used for engineer structures that can experience high pressure even in extreme cases (fires, sharp dynamic load and strikes). The images of the surface of hematite particles under the pressure of 5000 MPa, 10000 MPa, 15000 MPa and 20000 MPa were studied.

Abstract: The article touches upon the problem of raw materials for the ceramic industry. We have found alternative sources such as opoka-like rocks which are widely distributed in the South of Russia and the Volga region. The article presents the description of the characteristic features we identified in the process of compression molding opoka-like rocks of different types. The influence of compacting pressure on the density of pressed samples is given. There are conclusions about expediency of use of such raw materials for the development of ceramic industry.

Abstract: Oxygen (O₂) enriched air combustion via adaption of polymeric membranes has been proposed to be a feasible alternative to increase combustion proficiency while minimizing the emission of greenhouse gases into the atmosphere. Nonetheless, majority of techno-economic assessment on the O₂ enriched combustion evolving membrane separation process are confined to assumption of constant membrane permeance. In reality, it is well known that membrane permeance is highly dependent upon the temperature and pressure to which it is operated. Therefore, in this work, an empirical model, which includes the effect of temperature and pressure to permeance, has been evaluated based on own experimental work using polysulfone membrane. The empirical model has been further validated with published experimental results. It is found that the model is able to provide an excellent characterization of the membrane permeance across a wide range of operating conditions for both pure and binary gas with determination coefficient of minimally 0.99.