The main element of the hydraulic system is the pump, the reliability of which largely determines the reliability parameters of the entire hydraulic system. To ensure a high level of pump quality, it is necessary to c...
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The main element of the hydraulic system is the pump, the reliability of which largely determines the reliability parameters of the entire hydraulic system. To ensure a high level of pump quality, it is necessary to carry out tests at different stages of production: design and prototype development, construction modernization, and development of new pump models. Since most of the time is spent on testing, the urgent task is to reduce testing time and improve the quality of hydraulic equipment. This work aims to evaluate the factors determining pump longevity while ensuring the equivalence of accelerated and long-duration resource testing of pumps. The reduced wear of parts should be used to compare the technical condition of pumps subjected to accelerated and long-duration tests. The effect on the wear of the increase in the friction path per unit of time during accelerated tests must be considered. When comparing pumps that have undergone accelerated and long-duration tests, there will be some discrepancy in the parameters compared, the extent of which is used to conclude a positive or negative test result. A positive result of the conducted tests can be considered if none of the specific types of failure occurred during the testing process and if no fundamentally new defects are found during the examination of the developed pump. This methodology can guide accelerated tests of axial piston pumps: regulated and non-regulated with valve distribution at 320 bar, regulated pumps with end distribution at 200 bar, and regulated pumps with end distribution at 160 bar.
In contrast to previous methodologies utilizing smooth fractures for predicting production in fractured geothermal reservoirs, this study introduces a novel approach employing a non-uniform rough discrete fracture net...
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In contrast to previous methodologies utilizing smooth fractures for predicting production in fractured geothermal reservoirs, this study introduces a novel approach employing a non-uniform rough discrete fracture network model characterized by heterogeneous apertures. Partial differential equations governing dual porosity flow and heat transfer are formulated, followed by a multi-physical field coupling simulation for the reservoirscale formation model. The investigation focuses on the 50-year production performance of an enhanced geothermal system (EGS) under various parameters. Findings indicate a 15 % increase in production temperature with a 10-degree rise in injection temperature and a 10 % increase when well spacing is halved. Conversely, doubling the injection velocity or increasing the fracture aperture from 2 mm to 5 mm results in a 20 % and 25 % decrease in production temperature, respectively. These results highlight the negative impacts of faster fluid movement and larger fracture apertures on thermal retention. Conventional smooth fracture networks tend to underestimate both production temperature and the operational lifespan of EGS. An effective flow rate is defined, and an empirical prediction model for thermal recovery is established. This study provides valuable insights into the interplay of parameters affecting EGS production performance, serving as a pertinent reference for analyzing the influence of heterogeneous apertures on geothermal reservoirs.
Fundamental diagrams of vehicular traffic flow are generally multi-valued in the congested flow regime. We show that such set-valued fundamental diagrams can be constructed systematically from simple second order macr...
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Fundamental diagrams of vehicular traffic flow are generally multi-valued in the congested flow regime. We show that such set-valued fundamental diagrams can be constructed systematically from simple second order macroscopic traffic models, such as the classical Payne-Whitham model or the inhomogeneous Aw-Rascle-Zhang model. These second order models possess non-linear traveling wave solutions, called jamitons, and the multi-valued parts in the fundamental diagram correspond precisely to jamiton-dominated solutions. This study shows that transitions from function-valued to set-valued parts in a fundamental diagram arise naturally in well-known second order models. As a particular consequence, these models intrinsically reproduce traffic phases.
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