Journal articles: 'Thermo-hydraulic behaviour'

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Ketelsen, Søren, Sebastian Michel, Torben O. Andersen, Morten Kjeld Ebbesen, Jürgen Weber, and Lasse Schmidt. "Thermo-Hydraulic Modelling and Experimental Validation of an Electro-Hydraulic Compact Drive." Energies 14, no. 9 (April 22, 2021): 2375. http://dx.doi.org/10.3390/en14092375.

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Electro-hydraulic compact drives (ECDs) are an emerging technology for linear actuation in a wide range of applications. Especially within the low power range of 5–10 kW, the plug-and-play capability, good energy efficiency and small space requirements of ECDs render this technology a promising alternative to replace conventional valve-controlled linear drive solutions. In this power range, ECDs generally rely on passive cooling to keep oil and system temperatures within the tolerated range. When expanding the application range to larger power classes, passive cooling may not be sufficient. Research investigating the thermal behaviour of ECDs is limited but indeed required for a successful expansion of the application range. In order to obtain valuable insights into the thermal behaviour of ECDs, thermo-hydraulic simulation is an important tool. This may enable system design engineers to simulate thermal behaviour and thus develop proper thermal designs during the early design phase, especially if such models contain few parameters that can be determined with limited information available. Our paper presents a lumped thermo-hydraulic model derived from the conservation of mass and energy. The derived model was experimentally validated based on experimental data from an ECD prototype. Results show good accuracy between measured and simulated temperatures. Even a simple thermal model containing only a few thermal resistances may be sufficient to predict steady-state and transient temperatures with reasonable accuracy. The presented model may be used for further investigations into the thermal behaviour of ECDs and thus toward proper thermal designs required to expand the application range.

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Guo, Shao Hua. "The Coupled Thermo-Hydro-Mechanical Behavior of Saturated Fractured Solids." Applied Mechanics and Materials 204-208 (October 2012): 123–27. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.123.

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The stress equilibrium equation of anisotropic solids, coupled to the hydrodynamic seepage equation and heat transfer equation of saturated fractured rocks, are studied here based on the standard space of physical presentation, in which an new thermo-hydro-elastic model is induced. A set of uncoupled equation of heat and hydraulic propagations in anisotropic saturated fractured rocks is deduced. From them, two new phenomena of heat and hydraulic propagation are obtained, which are affected by both anisotropic subspaces of solids and thermo-mechanical and hydro-mechanical coupling coefficients. Based on these laws, we discuss the heat and hydraulic wave behaviour for isotropic solids.

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Thomas, H. R., and P. J. Cleall. "Inclusion of expansive clay behaviour in coupled thermo hydraulic mechanical models." Engineering Geology 54, no. 1-2 (September 1999): 93–108. http://dx.doi.org/10.1016/s0013-7952(99)00065-4.

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Paulech, Juraj, Vladimír Kutiš, Gabriel Gálik, Jakub Jakubec, and Tibor Sedlár. "Thermo-Hydraulic Behaviour of Coolant in Nuclear Reactor VVER-440 Under Refuelling Conditions." Strojnícky casopis – Journal of Mechanical Engineering 67, no. 1 (April 1, 2017): 87–92. http://dx.doi.org/10.1515/scjme-2017-0009.

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Abstract The paper presents the numerical simulation of thermo-hydraulic behaviour of coolant in the VVER- 440 nuclear reactor under standard outage conditions. Heating-up and flow of coolant between the reactor pressure vessel and spent fuel storage pool are discussed.

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Singh, Sanjay K., Manish Mishra, and PK Jha. "Experimental investigations on thermo-hydraulic behaviour of triple concentric-tube heat exchanger." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 229, no. 4 (April 16, 2014): 299–308. http://dx.doi.org/10.1177/0954408914531118.

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T’Joen, C., H. Huisseune, H. Canière, H. J. Steeman, A. Willockx, and M. De Paepe. "Interaction between mean flow and thermo-hydraulic behaviour in inclined louvered fins." International Journal of Heat and Mass Transfer 54, no. 4 (January 2011): 826–37. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2010.10.020.

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Hashemi, Amirhossein, and Melis Sutman. "Thermo-hydro-mechanical behaviour of partially saturated fine-grained soils in the context of energy geostructures." Soils and Rocks 45, no. 1 (February 18, 2022): 1–17. http://dx.doi.org/10.28927/sr.2022.076821.

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The multi-physical phenomena, particularly water content and temperature variations, governing the behaviour of soils should be considered in the design and analysis of the energy geostructures. Soil temperature and water content variations impose a significant risk on the stability and serviceability of existing and future geostructures. Although potential failure modes, impacts at a system scale, and the response of saturated soils to thermal loads are previously discussed, interpretation of the thermo-hydro-mechanical behaviour of partially saturated soils in the context of energy geostructures is not thoroughly investigated. In this regard, this paper brings together the experimental data from several laboratory investigations to attain a comprehensive understanding of the partially saturated fine-grained soils response under thermo-hydro-mechanical loading, which plays a vital role in the analysis of the soil behaviour and energy geostructures in contact with them. In this paper, the effect of thermal loading in different matric suctions and hydraulic loading at different temperatures on soil preconsolidation stress, water content variation, thermal and hydraulic conductivities, and compression indexes are studied. Furthermore, soil thermal deformation is studied in detail for different overconsolidation ratios and matric suctions.

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Liu, Kui, Renato Zagorščak, Richard J. Sandford, Oliver N. Cwikowski, Alexander Yanushkevich, and Hywel R. Thomas. "Insights into the Thermal Performance of Underground High Voltage Electricity Transmission Lines through Thermo-Hydraulic Modelling." Energies 15, no. 23 (November 24, 2022): 8897. http://dx.doi.org/10.3390/en15238897.

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In this paper, a flexible numerical framework to provide thermal performance assessment for the underground buried cables, considering different geological and meteorological conditions, has been presented. Underground cables tend to retain the heat produced in the conductor, so complex coupled thermo-hydraulic response of the porous medium surrounding the cables needs to be assessed to prevent cable overheating and the associated reduction in cable capacity for carrying current. Applying a coupled thermo-hydraulic model within the developed numerical framework to conduct a health assessment on a subset of National Grid Electricity Transmission’s underground cables, this study provides novel insights into the thermal behaviour of buried circuits. The results indicate that backfill and surrounding native soil have the dominant effect on the thermal behaviour of cables, while the amount of precipitation and ambient temperature were found to have less impact on cable’s thermal behaviour. The findings strongly infer that the nature of the overloading which is undertaken in practice would have no ongoing negative impact, suggesting that more frequent or longer duration overloading regimes could be tolerated. Overall, this study demonstrates how the developed numerical framework could be harnessed to allow safe rating adjustments of buried transmission circuits.

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CUEVAS, J., M. VILLAR, M. MARTIN, J. COBENA, and S. LEGUEY. "Thermo-hydraulic gradients on bentonite: distribution of soluble salts, microstructure and modification of the hydraulic and mechanical behaviour." Applied Clay Science 22, no. 1-2 (November 2002): 25–38. http://dx.doi.org/10.1016/s0169-1317(02)00109-6.

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Ghidaglia, Jean-Michel. "Long time behaviour of solutions of abstract inequalities: Applications to thermo-hydraulic and magnetohydrodynamic equations." Journal of Differential Equations 61, no. 2 (February 1986): 268–94. http://dx.doi.org/10.1016/0022-0396(86)90121-x.

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Thomas, H. R., Y. He, M. R. Sansom, and C. L. W. Li. "On the development of a model of the thermo-mechanical-hydraulic behaviour of unsaturated soils." Engineering Geology 41, no. 1-4 (January 1996): 197–218. http://dx.doi.org/10.1016/0013-7952(95)00033-x.

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Battistoni, P., P. Pavan, J. Mata-Alvarez, M. Prisciandaro, and F. Cecchi. "Rheology of sludge from double phase anaerobic digestion of organic fraction of municipal solid waste." Water Science and Technology 41, no. 3 (February 1, 2000): 51–59. http://dx.doi.org/10.2166/wst.2000.0055.

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In this paper experimental results on the anaerobic digestion of sewage sludge and organic fraction of municipal solid waste (OFMSW) by using a double phase process are reported. The long-term experiment has been carried out on a pilot scale plant, performed in different sets of operative conditions, during which granulometric distributions of particles in sludges and rheological properties of sludges were monitored. A significant fluidification of sludge was evidenced in the meso-thermo process, especially taking into account the variation in sludge behaviour from the first to the second phase. In the thermo-thermo process a fluidification higher than that shown in meso-thermo conditions is not observed, this suggesting that better results in terms of sludge conditioning can be obtained in a long time spent in thermophilic anaerobic digestion. Total volatile solids (TVS) and total fixed solids (TFS) become the most important parameters when mathematical modelling is applied to these processes.In the acidogenic phase, hydraulic retention time (HRT) and temperature are used to determine rigidity coefficient (RC), while only temperature is needed for yield stress (YC). Organic loading rate (OLR) and specific gas production (SGP) exert an important role in methanogenic phase description.

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Devillers, P., C. Saix, and M. S. El Youssoufi. "Loi de comportement thermo-hydromécanique pour les sols non saturés : identification in situ des indices de compression thermique." Canadian Geotechnical Journal 33, no. 2 (May 8, 1996): 250–59. http://dx.doi.org/10.1139/t96-004.

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This paper deals with thermo-hydromechanical behaviour of nonsaturated soils. The constitutive relationship presented herein allows for the prediction of the settlement or swell of an unsaturated soil under nonisothermal oedometric conditions. Mechanical, hydraulic, and thermal compression indexes are considered for stress, capillary pressure, and temperature variables, respectively. The implementation of the relationship in a prediction scheme requires preliminary characterization of these indexes. The stressstrain and water volume change relationships are first presented from semiempirical point of view for a nonsaturated soil element under nonisothermal conditions. These relationships allow for the expression of a thermo-hydromechanical constitutive law for nonsaturated soils and propose a relationship for the change in the soil water content. The thermal compression indexes are then determined for a clayey silty sand, first using a reverse method and then a direct method. This determination is made from experimental data recorded on a prototype involving heat storage in an aquifer. The values of these thermal compression indexes are finally compared with the laboratory values obtained in a thermal triaxial cell on samples of the same soil. Key words: nonsaturated soils, thermo-hydromechanical, oedometer tests, thermal compression indexes, characterization, reverse method, direct method.[Journal Translation]

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El-Zein, Abbas, Bowei Yu, and Ali Ghavam-Nasiri. "Insights into Desiccation and Self-Healing of Bentonite in Geosynthetic Clay Liners under Thermal Loads." E3S Web of Conferences 92 (2019): 03006. http://dx.doi.org/10.1051/e3sconf/20199203006.

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Geosynthetic Clay Liners (GCLs) are widely used for protecting groundwater from pollution sources at the surface, including applications in which they are subject to significant thermal gradients. Hence, sodium bentonite in the GCL may undergo significant dehydration and cracking, and the GCL might fail as a result. The paper presents outcomes of a set of recent experimental and numerical investigations exploring the propensity of bentonite to desiccate and self-heal, as well as means of mitigating the effect of thermal gradients on the hydraulic conductivity of GCLs. An elasto-plastic thermo-hydro-mechanical model was found to yield reasonable predictions of experimental behaviour, except for the transient phase of pre-heating hydration. Introducing an airgap between the GCL and the heat source can reduce the extent of desiccation and its effects on hydraulic conductivity. However, the effectiveness of the solution will depend on other factors including subgrade, magnitude of thermal and mechanical loads and type of GCL.

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Lang, Lin Zhi, Wiebke Baille, Snehasis Tripathy, and Tom Schanz. "Experimental study on the influence of preliminary desiccation on the swelling pressure and hydraulic conductivity of compacted bentonite." Clay Minerals 53, no. 4 (December 2018): 733–44. http://dx.doi.org/10.1180/clm.2018.53.

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ABSTRACTIn deep geological repositories, compacted bentonites have been proposed for use as barrier materials for isolating nuclear waste. The prevailing thermo-hydro-mechanical boundary conditions in the repositories may affect the swelling capacity and permeability of the compacted bentonites. In this study, the effect of preliminary desiccation on the subsequent hydro-mechanical behaviour (swelling pressure and hydraulic conductivity) of compacted Calcigel bentonite was investigated experimentally at 22°C and 80°C. In the first stage of the test, the compacted specimens were subjected to suction-controlled desiccation at 22°C and 80°C using the vapour-equilibrium technique. After the water content reached equilibrium at a given suction, the axial, radial and volumetric shrinkage strains were measured. Afterwards, constant-volume swelling-pressure tests were performed on the desiccated specimens (second test stage) by saturating the dried specimens with deionized water at 22°C and 80°C. At the end of the swelling-pressure test, the hydraulic conductivities of four saturated specimens were measured at each temperature. The volumetric shrinkage strain of the compacted bentonite during desiccation is controlled by suction instead of temperature. In addition, the preliminary desiccation increases both the swelling pressure and hydraulic conductivity of compacted bentonite, particularly if compacted bentonite undergoes extreme desiccation at an applied suction of >700 MPa.

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Bettella, Francesco, Gian Battista Bischetti, Vincenzo D'Agostino, Simone Virginio Marai, Enrico Ferrari, and Tamara Michelini. "Comparison of measurement methods of the front velocity of small-scale debris flows." Journal of Agricultural Engineering 46, no. 4 (December 18, 2015): 129. http://dx.doi.org/10.4081/jae.2015.472.

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Debris flow is a gravity-driven process, which is characterized by a travelling dense surge including large boulders, and it is followed by a more fluid tail. These characteristics make difficult the measurement of the mean flow velocity by means of common hydraulic techniques. Different methods can be used at real scale and small-scale to measure the front velocity but a dedicate comparison between available methods is still lacking. This research aims to compare the front velocity measurements in the transport zone of a miniature debris flow using three devices: i) a common digital video camera (29 frames per second); ii) a high speed thermo camera (60 fps); and iii) a laser photoelectric sensors system. The statistical analysis of data has highlighted no significant differences exist between front velocities obtained by means of the video camera and the thermo camera, whereas photocells data statistically differ from those achieved via the other systems. Some lack of data recorded by photocell was documented, while the thermo camera technique did not show significant loss of information being also helpful to detect the kinematic behaviour of single particles. Finally, the tests confirmed the influence of the solid volumetric concentration in the debris-flow mechanics, which promotes, <em>ceteris</em> <em>paribus</em>, the debris-flow slowing down.

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Blanco, A., A. Lloret, J. Carrera, and S. Olivella. "Thermo-hydraulic behaviour of the vadose zone in sulphide tailings at Iberian Pyrite Belt: Waste characterization, monitoring and modelling." Engineering Geology 165 (October 2013): 154–70. http://dx.doi.org/10.1016/j.enggeo.2013.05.022.

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Kulísek, Karel, Dominik Gazdič, and Karel Dvořák. "Effect of Fluidized Bed Ash on the Thermodynamic Stability of Hydraulic Binders." Materials Science Forum 908 (October 2017): 21–25. http://dx.doi.org/10.4028/www.scientific.net/msf.908.21.

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Fluidized bed ash, which is the youngest industrial waste can be considered on the basis of research, a high-quality secondary raw material base which can be easily used in the production of Portland cements and, in general, other hydraulic binders. Regarding the direct effect of anhydrite on the course of hydrating mixed cement with the fluidized fly ash and the consequent behaviour of the originated cement stone, its reaction with clinker materials on the mentioned Aft (Al2O3–Fe2O3-–tri) phase is clear. The creation of AFt phases, if they originate additionally, due to their morphology, is accompanied by significant volume changes which may lead to deformation up to the destruction of the cement stone. Some foreign publications show the possibility of the transformation of this thermo-dynamically unstable mineral into the further mineral from the group AFt phase, which is thaumasite, Ca3Si (CO3)(SO4)(OH)6.12H2O.

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Ghirian, Alireza, and Mamadou Fall. "Coupled thermo-hydro-mechanical–chemical behaviour of cemented paste backfill in column experiments. Part I: Physical, hydraulic and thermal processes and characteristics." Engineering Geology 164 (September 2013): 195–207. http://dx.doi.org/10.1016/j.enggeo.2013.01.015.

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Papafotiou, A., R. Senger, C. Li, A. Singh, B. Garitte, H. Müller, and P. Marschall. "A prediction–evaluation approach to the full-scale emplacement experiment (FE) in Mont Terri." Geological Society, London, Special Publications 482, no. 1 (November 8, 2018): 39–73. http://dx.doi.org/10.1144/sp482.10.

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AbstractA prediction–evaluation approach is developed to assess the propagation of parameter, conceptual and scenario uncertainties in the estimated near-field temperatures of the full-scale emplacement experiment at the Mont Terri rock laboratory. The uncertainty assessment is performed using a three-dimensional thermo-hydraulic numerical model of the full-scale emplacement experiment that represents the emplaced materials and surrounding Opalinus Clay and accounts for heat generation at the heaters. The propagation of parametric uncertainties is assessed using a first-order second-moment method supplemented by Monte Carlo simulations sampling the uncertain parameter space. The risk of uncertain parameters resulting in the failure of the maximum temperature criteria is evaluated with a first-order reliability method. Conceptual and scenario uncertainties are evaluated with deterministic simulation variants. After the conclusion of predictive modelling, a mid-term evaluation of the temperature predictions is performed through a comparison with measurements after 2.5 years of heating. The comparison indicates that the best estimates of temperature agree well with the measurements and that the 95% error bands assessed with parametric uncertainty envelope the measured values in almost all locations. Additional comparison with the measured degree of water saturation and the relative humidity is performed to assess the hydraulic behaviour and set the ground for the long-term evaluation, which will include predictions of the near-field pore pressures.

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Vidal, Catarina, and Virgínia Infante. "Role of Friction Stir Channel Geometry on the Fatigue Behaviour of AA5083-H111 at 120°C and 200°C." Advanced Materials Research 891-892 (March 2014): 1494–99. http://dx.doi.org/10.4028/www.scientific.net/amr.891-892.1494.

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Friction StirChannelling (FSC) is an innovative solid-state manufacturing technology able toproduce, in a single step, continuous integral channels in monolithic platesthat can be used to produce conformal cooling systems as well as heatexchanging devices. FSC is based on the same principles of Friction StirWelding (FSW) process and the features of the channels produced by FSC can becontrolled by the processing parameters and tool geometry. Bending fatiguetests have been performed using friction stir channelling specimens of 5083‑H111aluminium alloy with different channel geometries. Fatigue tests have beencarried out at 120°C and 200°C in a servo-hydraulic testing machine coupledwith a furnace, in order to understand the role of channel geometry on thefatigue behaviour at elevated temperature. Results were compared with thoseobtained at room temperature. The specimens were tested until fracture or up to 3x106 cycles. For the channel geometries tested, the fatiguestrength of friction stir channelling specimens is dependent on the testingtemperature, decreasing with the temperature increased. At all temperaturesstudied, for both channel geometries, fatigue-crack always initiated into theinterior of the specimen, namely on the boundary between the channel nugget andthe thermo‑mechanically affected zone. It was observed that crack initiationhas been occurred earlier at elevated temperature than at room temperature.

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Ferraro, Diego, Patricio Alberto, Eduardo Villarino, and Alicia Doval. "A multi-physics analysis for the actuation of the SSS in opal reactor." EPJ Nuclear Sciences & Technologies 4 (2018): 8. http://dx.doi.org/10.1051/epjn/2018003.

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OPAL is a 20 MWth multi-purpose open-pool type Research Reactor located at Lucas Heights, Australia. It was designed, built and commissioned by INVAP between 2000 and 2006 and it has been operated by the Australia Nuclear Science and Technology Organization (ANSTO) showing a very good overall performance. On November 2016, OPAL reached 10 years of continuous operation, becoming one of the most reliable and available in its kind worldwide, with an unbeaten record of being fully operational 307 days a year. One of the enhanced safety features present in this state-of-art reactor is the availability of an independent, diverse and redundant Second Shutdown System (SSS), which consists in the drainage of the heavy water reflector contained in the Reflector Vessel. As far as high quality experimental data is available from reactor commissioning and operation stages and even from early component design validation stages, several models both regarding neutronic and thermo-hydraulic approaches have been developed during recent years using advanced calculations tools and the novel capabilities to couple them. These advanced models were developed in order to assess the capability of such codes to simulate and predict complex behaviours and develop highly detail analysis. In this framework, INVAP developed a three-dimensional CFD model that represents the detailed hydraulic behaviour of the Second Shutdown System for an actuation scenario, where the heavy water drainage 3D temporal profiles inside the Reflector Vessel can be obtained. This model was validated, comparing the computational results with experimental measurements performed in a real-size physical model built by INVAP during early OPAL design engineering stages. Furthermore, detailed 3D Serpent Monte Carlo models are also available, which have been already validated with experimental data from reactor commissioning and operating cycles. In the present work the neutronic and thermohydraulic models, available for OPAL reactor, are coupled by means of a shared unstructured mesh geometry definition of relevant zones inside the Reflector Vessel. Several scenarios, both regarding coupled and uncoupled neutronic & thermohydraulic behavior, are presented and analyzed, showing the capabilities to develop and manage advanced modelling that allows to predict multi-physics variables observed when an in-depth performance analysis of a Research Reactor like OPAL is carried out.

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Shabi, Linart, Juliane Weber, and Jürgen Weber. "Simulative Study of Different Control Concepts of Cooling System for Machine Tools." MATEC Web of Conferences 220 (2018): 08002. http://dx.doi.org/10.1051/matecconf/201822008002.

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Power losses in machine tools, e.g. during the standby, idle-, and manufacturing process, are converted into heat energy. This causes the machine frame and other machine components to heat up. As a result, the Tool Centre Point (TCP) of the machine tools is moved. The accuracy of the machine is thus reduced during manufacturing. The current cooling system design of machine tools is based on a centrally fixed pump supply that provides a constant cooling volume flow for cooling all the machine tool components. This does not correspond to the individual temperature development of the components, after all, the high temperature fluctuation arises and causes the thermo-elastic deformation of machine tools. The main objective of this paper is to highlight the deficit of the current concept of cooling systems and to present a simulative study on the different controls concepts of cooling systems for machine tools. The results depict that the new concepts under consideration have a large potential for better thermal behaviour and lower hydraulic performance compared to the current cooling system design. The simulation results show a stability of the components’ temperature profile as well as a decreased energy consumption of the cooling system.

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Scarfone, Riccardo, Simon J. Wheeler, and Colin C. Smith. "Numerical study of the application of capillary barrier systems for prevention of rainfall-induced slope instabilities." E3S Web of Conferences 195 (2020): 01027. http://dx.doi.org/10.1051/e3sconf/202019501027.

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Slope instability is often caused by decreases in suction due to heavy and prolonged rainfall. In this study, the application of capillary barrier systems (CBSs) for suction control and slope stabilization purposes (i.e. reducing the risk of rainfall-induced slope instabilities) is analysed, due to their capacity to limit the percolation of water into the underlying soil. The behaviour of two slopes was studied numerically: a bare slope made of fine-grained soil and the same slope covered by a capillary barrier system. The time evolution of suction in the slopes subjected to realistic atmospheric conditions was studied by performing numerical finite element analyses with Code_Bright. In particular, multi-phase multi-physics thermo-hydraulic analyses were performed, modelling the soil-atmosphere interaction over periods of many years. Suction and degree of saturation distributions obtained from these analyses were then exported to the software LimitState GEO, which was used to perform limit analysis to assess the stability of the slopes. The CBS was able to limit the percolation of water into the slope and was shown to be effective in increasing the minimum values of suction attained in the underlying ground, resulting in improved stability of the slope.

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Kumar S, Santhosh, and Somashekhar S. Hiremath. "Temperature-dependent rheological properties of viscoelastic polymer based flexible abrasive media for finishing process." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 235, no. 4 (January 24, 2021): 973–85. http://dx.doi.org/10.1177/0954408920987904.

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The objective of the present investigation is to develop and study the thermal and rheological properties of the in-house developed flexible abrasive media. It is a mixer of viscoelastic polymer and plasticizer mixed with micro-abrasive particles, used for removing debris and irregularities present on internal and external complex surfaces used in the aerospace, automotive and medical industries. This paper presents, morphology of the developed abrasive media is captured using the Scanning Electron Microscope (SEM), thermal properties of the abrasive media are studied using Thermo Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) analysis along with tensile properties of the abrasive media ascertained using the universal testing machine. The rheological properties of the media play a major role in media flow over the intricate shapes and removing the material from the surface. To understand the media behavior, further rheological properties such as viscosity, shear stress, storage modulus, loss modulus, loss tangent, and complex viscosity are ascertained with varying shear rate and frequency at different temperature using rheometer. The TGA and DSC results shows abrasive media has good thermal stability and possibility of using the media for finishing process under lower temperature <100 °C. Rheological studies shows the shear thinning behaviour of the media and elastic solid behavior (G′ > G′′) at different temperatures which is suitable for finishing the complex internal and the external features efficiently and effectively. The developed abrasive media is used to finish the hydraulic components which are difficult to access with conventional tools and the results of finishing process are presented.

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Aritomi, Masanori, Akira Inoue, Shigebumi Aoki, and Keiji Hanawa. "Thermo-hydraulic behavior of inverted annular flow." Nuclear Engineering and Design 120, no. 2-3 (June 1990): 281–91. http://dx.doi.org/10.1016/0029-5493(90)90380-g.

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Agwu Nnanna, A. G. "Thermo-Hydraulic Behavior of Microchannel Heat Exchanger System." Experimental Heat Transfer 23, no. 2 (March 12, 2010): 157–73. http://dx.doi.org/10.1080/08916150903402823.

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Acosta Martínez, Leonardo, Carlos Rafael García Hernández, Jesus Rosales García, and Annie Ortiz Puentes. "Thermo-hydraulic Simulation of AP1000 Nuclear Reactor Fuel Assembly." VETOR - Revista de Ciências Exatas e Engenharias 31, no. 1 (November 18, 2021): 60–71. http://dx.doi.org/10.14295/vetor.v31i1.13576.

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One of the challenges of future nuclear power is the development of safer and more efficient nuclear reactor designs. The AP1000 reactor based on the PWR concept of generation III + has several advantages, which can be summarized as: a modular construction, which facilitates its manufacture in series reducing the total construction time, simplification of the different systems, reduction of the initial capital investment and improvement of safety through the implementation of passive emergency systems. Being a novel design it is important to study the thermohydraulic behavior of the core applying the most modern tools. To determine the thermohydraulic behavior of a typical AP1000 fuel assembly, a computational model based on CFD was developed. A coupled neutronic-thermohydraulic calculation was performed, allowing to obtain the axial power distribution in the typical fuel assembly. The geometric model built used the certified dimensions for this type of installation that appear in the corresponding manuals. The thermohydraulic study used the CFD-based program ANSYS-CFX, considering an eighth of the fuel assembly. The neutronic calculation was performed with the program MCNPX version 2.6e. The work shows the results that illustrate the behavior of the temperature and the heat transfer in different zones of the fuel assembly. The results obtained agree with the data reported in the literature, which allowed the verification of the consistency of the developed model.

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Zagorščak, Renato, Majid Sedighi, and Hywel R. Thomas. "Effects of Thermo-Osmosis on Hydraulic Behavior of Saturated Clays." International Journal of Geomechanics 17, no. 3 (March 2017): 04016068. http://dx.doi.org/10.1061/(asce)gm.1943-5622.0000742.

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Rahman, M. M., M. S. Hussain, M. A. Imtiaz, and M. Q. Huda. "Computational analysis of thermo-hydraulic behavior of TRIGA research reactor." Annals of Nuclear Energy 49 (November 2012): 48–56. http://dx.doi.org/10.1016/j.anucene.2012.05.034.

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ZHAO, C. L., P. GUO, and F. LONG. "THERMO-HYDRAULIC COUPLED SIMULATION OF IMMISCIBLE CO2 FLOODING." Applied Ecology and Environmental Research 17, no. 1 (2019): 409–25. http://dx.doi.org/10.15666/aeer/1701_409425.

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Zhu, Xiao Feng, Yong Zhang, Zhao Feng Lu, and Yong Ma. "Coefficient Identification of Steam Network Model Based on Genetic Algorithm." Advanced Materials Research 658 (January 2013): 555–59. http://dx.doi.org/10.4028/www.scientific.net/amr.658.555.

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This article establish a coupled thermo-hydraulic mathematical model for steam network by adopting a set of equations. Here, identification is defined as process in which a number of Steam Network model parameters are adjusted until the model mimics behavior of the real Steam Network as closely as possible. Test result indicates the advantage of genetic algorithm.

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Norouzi, Ali, Javad Sodagar-Abardeh, Ahmad Arabkoohsar, and Kamal Abdel Radi Ismail. "Investigating thermo-hydraulic behavior of pillow plate heat exchangers using entropy generation approach." Chemical Engineering and Processing - Process Intensification 174 (April 2022): 108887. http://dx.doi.org/10.1016/j.cep.2022.108887.

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Oorthuis, Raül, Jean Vaunat, Marcel Hürlimann, Antonio Lloret, José Moya, Càrol Puig-Polo, and Alessandro Fraccica. "Slope Orientation and Vegetation Effects on Soil Thermo-Hydraulic Behavior. An Experimental Study." Sustainability 13, no. 1 (December 22, 2020): 14. http://dx.doi.org/10.3390/su13010014.

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The stability and erosion of natural and man-made slopes is influenced by soil-vegetation-atmosphere interactions and the thermo-hydro-mechanical slope conditions. Understanding such interactions at the source of slope mass-wasting is important to develop land-use planning strategy and to promote environmentally adapted mitigation strategies, such as the use of vegetation to stabilize slopes and control erosion. Monitoring is essential for calibrating and validating models and for better comprehending the physical mechanisms of soil-vegetation-atmosphere interactions. We approached this complex problem by means of an experimental work in a full-scale monitored embankment, which is divided into four instrumented partitions. These partitions are North or South-faced and present a bare and vegetation cover at each orientation. Our main findings show that vegetation enhances rainfall infiltration and decreases runoff, which reduces slope stability and surficial erosion, while plant transpiration induces higher suctions and hence slope stability. Concerning thermal aspects, vegetation reduces the incidence of net solar radiation and consequently heat flux. Thus, daily temperature fluctuations and evaporation decreases. However, the effect of vegetation in the development of dryer soil conditions is more significant than the orientation effect, presenting higher drying rates and states at the North-vegetated slope compared to the South-bare slope.

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Ahmed I. ElShafei, Amr Guaily, and Mohammed A. Boraey. "Turbulent Axisymmetric Non-Isothermal Flow of The Hitec Molten Salt with Temperature Dependent Properties: A Numerical Investigation." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 86, no. 2 (August 22, 2021): 1–14. http://dx.doi.org/10.37934/arfmts.86.2.114.

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This study aims to investigate the Hitec molten salt’s thermal-hydraulic behavior in a smooth round pipe under broad ranges of surface heat flux and Reynolds number (q = 104 – 105 W/m2, Re = 104 – 105). Mesh independent study was performed to ensure the robustness of the model to achieve accurate solutions. Presentation of temperature, pressure and thermophysical properties for multiple cases are presented and discussed. Temperature gradient decreases at high Reynolds number leading to small change in thermo-physical properties. While pressure seems not to be affected by the change in the applied surface heat flux, it increasess linearly across the pipe with the increase in Reynolds number. This analysis aims to provide better understanding of the thermal-hydraulic behavior for fluids with temperature dependent properties for a wide range of Re and surface heat flux.

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Chauhan, Parul, Elio Moussa, Noémie Prime, Simon Wheeler, and Olivier Plé. "Simulating the drying behavior of rammed earth columns." E3S Web of Conferences 195 (2020): 01025. http://dx.doi.org/10.1051/e3sconf/202019501025.

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Rammed earth construction provides an efficient alternative construction material to limit energy consumption and CO2 emission. It possesses various characteristics of a sustainable material, but its mechanical capacity is sensitive to humidity variations. It is, therefore, important to better understand water transport within rammed earth when subjected to varying ambient conditions. In this context, the present work aims to analyze the hydraulic behavior of a reduced piece of rammed earth wall consisting of a column of size 14cm x 14cm x 30cm subjected to drying from the initial compaction water content in an indoor environment. The columns had transient non-uniform relative humidity, which was measured in-situ. Thermo-hydraulic coupled numerical modeling was developed using realistic atmospheric boundary conditions. The material and hydric parameters were chosen from an experimental study previously performed at the material scale. A parametric study was performed in order to evaluate the sensitivity of the modeling to both material parameters and boundary conditions. The results of the numerical simulations were highly sensitive to parameter values used for the water retention curve and the surface mass transfer coefficient, with a satisfactory matching of experimental results only achieved after adjusting initial estimates of relevant parameter values.

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Khan, Asif, and Muddassir Ali. "Thermo-hydraulic behavior of alumina/silica hybrid nanofluids through a straight minichannel heat sink." Case Studies in Thermal Engineering 31 (March 2022): 101838. http://dx.doi.org/10.1016/j.csite.2022.101838.

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Fernández-Seara, José, and Rubén Diz. "Thermo-hydraulic behavior of ice slurry in an offset strip-fin plate heat exchanger." International Journal of Refrigeration 41 (May 2014): 171–80. http://dx.doi.org/10.1016/j.ijrefrig.2013.12.011.

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Guo, Qi Feng, Fen Hua Ren, and Zhao Cai Zhang. "Stabality Analysis of Deep Roadway Based on Coupled Thermo-Hydro-Mechanical Behaviors." Advanced Materials Research 594-597 (November 2012): 2564–68. http://dx.doi.org/10.4028/www.scientific.net/amr.594-597.2564.

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In order to research the stability of excavation in deep mines under high ground stress, high rock temperature and high karst hydraulic, the interaction of stress field, seepage field and temperature field are discussed through basic constitutive relation, seepage equation, thermometer equation and coupled thermo-hydro-mechanical equation. A numerical model was built to simulate the excavation of deep roadway. The result shows that the simulated ground stress based on three fields coupled is much closer to the field measured value and the change of stress and displacement caused by the excavation are limited which is about same as the later monitoring.

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Saha, Sandip, Vallampati Ramachandra Prasad, and Osman Anwar BÃ©g. "THERMAL ANALYSIS OF LAMINAR WATER FLOW OVER A BACKWARD FACING CHANNEL WITH CARBON NANOPARTICLES." Journal of the Serbian Society for Computational Mechanics 16, no. 1 (November 1, 2022): 125–37. http://dx.doi.org/10.24874/jsscm.2022.16.01.09.

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In the last few years, the thermo-hydraulic simulation of nanofluid flow bifurcation phenomena has become of great interest to researchers and a useful tool in many engineering applications. FVM has been employed in this article to numerically explore the laminar water flow over a backward facing channel with or without carbon nanoparticles (CN). The problem formulated in this paper has been solved by considering the effects of nanoparticle weight percentages (ð‘¤%), such as 0.00, 0.12, and 0.25 for different Reynolds number (ð‘…ð‘’). Nusselt number distribution (ð‘ð‘¢(ð‘¥)), coefficient of skin friction (ð¶ð‘“), characteristics of pressure drop (Î”ð‘), velocity contours, static temperature, pumping power (ð‘ƒð‘) and thermal resistance factor (ð‘…) have been investigated to know the behavior of thermo-hydraulic flow bifurcation phenomena. The present study shows that the surface temperature and coefficient of heat transfer can be reduced due to the effect of ð‘…ð‘’ or w%. For different w%, it has been found that in the rise in the values of ð‘…ð‘’ causes the increase of vortex length and as a result velocity gradient and Î”ð‘ arises. Furthermore, it has also been studied that the enhancement of ð‘…ð‘’ causes the increaseof ð‘ƒð‘ and Î”ð‘.

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Habibi Khalaj, Ali, Ali Chaibakhsh, Hoseyn Sayyaadi, and M. R. Jafari Nasr. "THERMO-HYDRAULIC BEHAVIOR MODELING OF PASSIVE HEAT TRANSFER ENHANCEMENT TECHNIQUES USING A SOFT COMPUTING APPROACH." Chemical Engineering Communications 201, no. 1 (September 30, 2013): 53–71. http://dx.doi.org/10.1080/00986445.2012.762624.

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Sepehrnia, Mojtaba, Hossein Khorasanizadeh, and Mohammad Behshad Shafii. "Effect of transverse and parallel magnetic fields on thermal and thermo-hydraulic performances of ferro-nanofluid flow in trapezoidal microchannel heat sink." International Journal of Numerical Methods for Heat & Fluid Flow 31, no. 7 (May 18, 2021): 2089–111. http://dx.doi.org/10.1108/hff-12-2019-0907.

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Purpose This paper aims to study the thermal and thermo-hydraulic performances of ferro-nanofluid flow in a three-dimensional trapezoidal microchannel heat sink (TMCHS) under uniform heat flux and magnetic fields. Design/methodology/approach To investigate the effect of direction of Lorentz force the magnetic field has been applied: transversely in the x direction (Case I);transversely in the y direction (Case II); and parallel in the z direction (Case III). The three-dimensional governing equations with the associated boundary conditions for ferro-nanofluid flow and heat transfer have been solved by using an element-based finite volume method. The coupled algorithm has been used to solve the velocity and pressure fields. The convergence is reached when the accuracy of solutions attains 10–6 for the continuity and momentum equations and 10–9 for the energy equation. Findings According to thermal indicators the Case III has the best performance, but according to performance evaluation criterion (PEC) the Case II is the best. The simulation results show by increasing the Hartmann number from 0 to 12, there is an increase for PEC between 845.01% and 2997.39%, for thermal resistance between 155.91% and 262.35% and ratio of the maximum electronic chip temperature difference to heat flux between 155.16% and 289.59%. Also, the best thermo-hydraulic performance occurs at Hartmann number of 12, pressure drop of 10 kPa and volume fraction of 2%. Research limitations/implications The embedded electronic chip on the base plate generates heat flux of 60 kW/m2. Simulations have been performed for ferro-nanofluid with volume fractions of 1%, 2% and 3%, pressure drops of 10, 20 and 30 kPa and Hartmann numbers of 0, 3, 6, 9 and 12. Practical implications The authors obtained interesting results, which can be used as a design tool for magnetohydrodynamics micro pumps, microelectronic devices, micro heat exchanger and micro scale cooling systems. Originality/value Review of the literature indicated that there has been no study on the effects of magnetic field on thermal and thermo-hydraulic performances of ferro-nanofluid flow in a TMCHS, so far. In this three dimensional study, flow of ferro-nanofluid through a trapezoidal heat sink with five trapezoidal microchannels has been considered. In all of previous studies, in which the effect of magnetic field has been investigated, the magnetic field has been applied only in one direction. So as another innovation of the present research, the effect of applying magnetic field direction (transverse and parallel) on thermo-hydraulic behavior of TMCHS is investigated.

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Qi, Cong, Jinghua Tang, Fan Fan, and Yuying Yan. "Effects of magnetic field on thermo-hydraulic behaviors of magnetic nanofluids in CPU cooling system." Applied Thermal Engineering 179 (October 2020): 115717. http://dx.doi.org/10.1016/j.applthermaleng.2020.115717.

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Hueckel, Tomasz A. "Water–mineral interaction in hygromechanics of clays exposed to environmental loads: a mixture-theory approach." Canadian Geotechnical Journal 29, no. 6 (December 1, 1992): 1071–86. http://dx.doi.org/10.1139/t92-124.

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Water–mineral interaction in narrow interstices (<30 Å (1 Å = 0.1 nm)) in dense, saturated clays is discussed in view of recent experimental findings and molecular dynamics simulations. Consequences to the macroscopic behavior are considered. A mixture theory for two interacting constituents is developed. Effects of temperature and chemicals are discussed. A postulate of mass transfer of adsorbed water from solid to fluid fraction caused by thermal or chemical load is then discussed. Theory of plasticity of clays affected by heat or chemicals is developed to deal with the effects of thermal and chemical consolidation. Key words : hydraulic conductivity, effective stress, environmental loads, thermo-chemo-plasticity.

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Qasim, M. S., S. G. Ali, and B. Freegah. "Conical Spring Inserts Effect on the Thermo- hydraulic Characteristics in Circular Copper Tube." IOP Conference Series: Materials Science and Engineering 1182, no. 1 (October 1, 2021): 012065. http://dx.doi.org/10.1088/1757-899x/1182/1/012065.

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Abstract Experimental and numerical investigation was conducted to study the thermo-hydraulic characteristics in circular tube fitted with conical spring inserts. The dimensions of circular copper tube are 100cm, 2.2cm and 2.4 cm which represent the length, inner and outer diameters respectively. The length of insert was 15cm, while the conical spring has 16mm diameter gradually decreases to 6mm with the length and the pitch between the coils was 20mm. The diameter of wire used to fabricate the conical spring insert was 4mm. Those inserts were arranged into eight categories (A1 to A8). In the numerical part, the governing equations were solved by using commercial ANSYS-Fluent package (2019 R3) with the assistance of solid works and Gambit software program. The finite volume approach was used in solving the equations to predict the pressure flow, heat transfer and temperature distribution along the tube. Experimental work included design and built a test platform for the experimental measurements. The aim of experimental study was to predict the behavior of heat transfer and pressure in the tube with two cases, plain tube and inserted tube at the effect of different parameters. All experimental tests were conducted at turbulent flow fully developed. The range of Reynolds number and heat flux were (3542-7522) (4549-10576 W/m^2) respectively. The results showed that the best augmentation in heat transfer was by using a category A5 of conical spring insert compared with plain tube. Results show good agreement between the numerical and experimental results with an error of 8%. Also results showed that the Nusselt number increases as the Reynolds number increasing.

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Kumar, Prashant, and Frédéric Topin. "About Thermo-Hydraulic Properties of Open Cell Foams: Pore Scale Numerical Analysis of Strut Shapes." Defect and Diffusion Forum 354 (June 2014): 195–200. http://dx.doi.org/10.4028/www.scientific.net/ddf.354.195.

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The thermo-physical behavior of open-celled metal foams depends on their microscopic structure. Various ideal periodic isotropic structures of tetrakaidecahedron shapes with constant cross section of the ligament having circular, square, diamond, hexagon and star strut shapes with various orientations are studied. We have proposed a generalized analytical model in order to obtain geometrical parameters correctly and various relationships between different geometrical parameters and porosities (60-95%) are presented. We have also studied the flow parameters namely permeability and inertia coefficient for different strut shapes and various Reynolds number (0.00001<Re<3000). The range of solid to fluid phase conductivity ratios (λs/λf) studied is from 10 to 30000 for different porosities in local thermal equilibrium condition and an analytical correlation is proposed comprising geometrical parameters of foam structure.

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Ma, Yong, Yan Guang Sun, and Li Ye Yu. "Pressure Drop Coefficient Identification of Steam Network Model Based on Genetic Algorithm." Applied Mechanics and Materials 271-272 (December 2012): 1388–92. http://dx.doi.org/10.4028/www.scientific.net/amm.271-272.1388.

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This article establish a coupled thermo-hydraulic mathematical model for steam network by adopting a set of equations The model is simplified according to steam flow features in pipe networks. It is concluded that coupled iteration can be employed in steam network. It is well-known fact that, Steam Network mathematical model must be identified first. Here, identification is defined as process in which a number of Steam Network model parameters are adjusted until the model mimics behavior of the real Steam Network as closely as possible. The case study demonstrates that the integrated identification method gives modelers the maximum flexibility to improve the model accuracy and robustness. Test result indicates the advantage of genetic algorithm.

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Wang, Qiqi, Mian Chen, Botao Lin, Yong Huang, and Sen Chen. "Vertical Well Assisted Hydraulic Fracturing in Mudstone Interlayer of Terrestrial Ultra-heavy Oil Reservoir." IOP Conference Series: Earth and Environmental Science 1124, no. 1 (January 1, 2023): 012126. http://dx.doi.org/10.1088/1755-1315/1124/1/012126.

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Abstract The widely developed impermeable interlayers hinder the migration of steam and condensate in a steam stimulation project, bringing the difficulty of developing the formation part overlying the interlayer. Hydraulic fracturing the interlayer through an existing neighboring observation (vertical) well can break through the interlayer without significantly increasing the budget. In this study, the laboratory test results of true triaxial hydraulic fracturing experiments and CT tests were analyzed to investigate the fracture propagation in the oil sand-mudstone multi-layer samples. A geological model was established to simulate the crack expansion using the finite element (FE) method by employing the cohesive element to represent fracture apertures. Furthermore, the geological model after the fracturing treatment was imported to a thermo-hydro-mechanical simulator to predict its mechanical and production behavior under steam circulation. It was found from laboratory experiments that the hydraulic fractures that initiated in the mudstone layer effectively propagated into the oil sand layer. The FE simulation shows that vertical fractures can be formed under field stress conditions. The fracture would extend into the overlying and underlying oil sand layers passing through the lithological interface. Accordingly, the fractures caused by hydraulic fracturing treatment can accelerate the diffusion of injected steam and the flow of crude oil after substantial viscosity reduction by steam heating. Future research is dedicated to generating a more complex fracture network in the mudstone interlayer so that the oil and steam flow paths can be strengthened considerably.

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Lohrasbi, Sina, René Hammer, Werner Eßl, Georg Reiss, Stefan Defregger, and Wolfgang Sanz. "Thermo-Hydraulic Characteristics of Micro-Scale Surface Roughness Topology of Additively Manufactured Surface Model: Modal Decomposition Perspective." Energies 14, no. 22 (November 16, 2021): 7650. http://dx.doi.org/10.3390/en14227650.

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As a consequence of rapid development of additive manufacturing (3D printing) methods, the academic/industrial demand has been continuously increasing. One field of application is the manufacturing of heat exchanging devices using this promising method. In this regard, understanding the underlying mechanisms from a thermo-hydraulic viewpoint becomes important. Therefore, in this study, scale-resolving large eddy simulation (LES) is applied to reveal the flow details in combination with a model of roughness topology occurring in additive manufacturing. To process the transient LES results, proper orthogonal decomposition (POD) is used to extract the coherent flow structures, and the extended POD is used to rank the flow modes based on thermal importance. The main aim of the present work is to go beyond the conventionally applied methodologies used for the evaluation of surface roughness, i.e., averaged numerical study or experimental overall performance evaluation of the flow/thermal response of additively manufactured surfaces in heat exchangers. This is necessary to reveal the underlying flow mechanisms hidden in the conventional studies. In this study, the behavior of the flow over the micro-scale surface roughness model and its effects on heat transfer are studied by assuming cone-shaped roughness elements with regular placement as the dominant surface roughness structures. The major discussions reveal the footprint of flow mechanisms on the heat transfer coefficient spatial modes on the rough surface. Moreover, comparative study on the flow/thermal behavior at different levels of roughness heights shows the key role of the height-to-base-diameter ratio of the roughness elements in thermal performance.

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Yu, Huajie, Lu Li, Qionghui Tang, Yue Peng, and Yinshi Li. "Transient Behaviors of Thermo-Hydraulic and Thermal Stratification in the Pressurizer Surgeline for the Nuclear Power Plant." Journal of Thermal Science 31, no. 2 (March 15, 2022): 344–58. http://dx.doi.org/10.1007/s11630-022-1536-6.

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Journal articles on the topic 'Thermo-hydraulic behaviour'

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