Gotowe bibliografie tematyczne / WATER PRESSURE HEAD

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Gotowa bibliografia na temat „WATER PRESSURE HEAD”

Autor: Grafiati
Data publikacji: 11 września 2023

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Artykuły w czasopismach na temat "WATER PRESSURE HEAD"

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Szada-Borzyszkowska, Monika, Wojciech Kacalak, Dariusz Lipiński i Błażej Bałasz. "Analysis of the Erosivity of High-Pressure Pulsating Water Jets Produced in the Self-Excited Drill Head". Materials 14, nr 15 (27.07.2021): 4165. http://dx.doi.org/10.3390/ma14154165.

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The dynamic impact of a water jet with a periodically changing structure can be used in various industries. The paper presents a design solution for a self-excited pulse head. This head can be used in mining for drilling holes and breaking rocks. The design of the head was developed based on computer simulations, which made it possible to learn the mechanism of impulse shaping inside the head. Tests of the water jet produced in the self-excited pulsation head showed the occurrence of periodic changes in its internal structure and pulsation frequency. A significant increase in the dynamic stream pressures was demonstrated for the head working in the water environment compared to the head working in the air environment For example, for nominal medium and highest pressures, this increase is up to 82%, while for the lowest pressures (10 MPa), the pressure force values increase by 46%. It was found that an increase in the nominal water pressure causes a decrease in the frequency of hydrodynamic pulses in the head operating in both the water and air environment.
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Zhang, Kai, Bo Song i Delan Zhu. "The Development of a Calculation Model for the Instantaneous Pressure Head of Oscillating Water Flow in a Pipeline". Water 11, nr 8 (31.07.2019): 1583. http://dx.doi.org/10.3390/w11081583.

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Sinusoidal oscillating water flow at low pressure can improve the anti-clogging ability of an emitter in drip irrigation or the water distribution of a nozzle in sprinkler irrigation and reduce the cost and energy consumption of the irrigation system. In this study, the characteristics of instantaneous pressure head attenuation of oscillating water flow along a pipeline have been investigated. By using a complex function to solve the continuity equation and the momentum equation of a pipeline with water hammer motion and using the Darcy–Weisbach formula to estimate the head loss, a calculation model for the instantaneous pressure head of oscillating water flow along a pipeline was developed. The measured value of the amplitude of the pressure head and the average instantaneous pressure head in the experiments have been used to verify the corresponding pressure head calculated by the model. The results show that the amplitude of the pressure head and the average instantaneous pressure head decrease linearly along the pipeline. The calculated value of the amplitude of the pressure head and the average instantaneous pressure head are basically close to the corresponding measured pressure head. From the results of all the tests, the maximum relative error of the calculated and measured value of the amplitude of the pressure head along the pipeline was 9.44%. The maximum relative error of the calculated and measured value of the average instantaneous pressure head along the pipeline was 8.37%. Hence, the model can accurately predict the instantaneous pressure head of oscillating water flow along a pipe and provide a theoretical basis for the application of oscillating water flow in irrigation systems and the design of irrigation pipe networks.
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Bicejova, Luba, i Slavko Pavlenko. "Water Jet Technology Head Vibration due to Water Pressure Change". Advanced Materials Research 1061-1062 (grudzień 2014): 511–14. http://dx.doi.org/10.4028/www.scientific.net/amr.1061-1062.511.

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The following paper analyses effects of pressure values of a high pressure pump on technology head vibrations origin at hydroabrasive erosion in production process. The aim is to focus onto one of possible sources of undesirable vibrations which can be subsequently influencing the cutting surface quality.
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Miki, K., M. R. Klocke, S. K. Hong i J. A. Krasney. "Interstitial and intravascular pressures in conscious dogs during head-out water immersion". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 257, nr 2 (1.08.1989): R358—R364. http://dx.doi.org/10.1152/ajpregu.1989.257.2.r358.

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Water immersion (WI) causes an increase in plasma volume in humans and dogs. To determine the mechanism for this fluid movement, the transmission of external water hydrostatic pressure to the interstitial and vascular compartments was studied in six conscious dogs. Systemic arterial, central venous, peripheral arterial (ulnar artery) and venous (cephalic vein), pleural, intra-abdominal, and interstitial fluid hydrostatic (by Guyton's capsule and wick catheter method) pressures and external reference water pressure were measured at three different levels of WI: 1) extremities only, 2) midchest, and 3) midcervical levels at 37 degrees C. There was a significant linear relationship between interstitial fluid hydrostatic pressure (X) and external water pressure (Y): (Y = 0.86X + 1.4, r = 0.93 by Guyton's capsule; Y = 0.85X + 2.4, r = 0.93 by wick catheter. However, vascular pressures did not change when dogs were immersed at the level of the extremities. These pressures increased only during WI at the midchest and midcervical levels. Therefore the pressure gradient that develops between the interstitial and intravascular compartments is probably the major reason for the transcapillary fluid shift during WI.
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Chang, Dong Eil, Do Guen Yoo i Joong Hoon Kim. "A Study on the Practical Pressure-Driven Hydraulic Analysis Method Considering Actual Water Supply Characteristics of Water Distribution Network". Sustainability 13, nr 5 (5.03.2021): 2793. http://dx.doi.org/10.3390/su13052793.

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For reliable pressure-driven analysis (PDA) results, it is necessary to reasonably determine an objective head-outflow relationship (HOR) and the required head for each node. So far, no methodology has been proposed to objectively determine two factors based on data of real block. In this study, the HOR was defined using the water supply method, residential environment, and water consumption data within real blocks. The standard minimum residual pressure criteria were reviewed to quickly and rationally determine the required head for each node. To validate the proposed methodology, the HOR and required head application conditions were configured for different scenarios; the available flow rate of nodes and the water supply capacity of the entire block were evaluated based on PDA results. Through the results for each scenario, the HOR definition method was able to provide a reasonable result reflecting the actual block’s conditions, unlike the conventional orifice-type HOR, and the standard minimum residual pressure criteria as the required head was evaluated to be more efficient than the conventional time-consuming method. The HOR uncertainty and the lack of rationality in the selection of the required heads affected the reliability of PDA results; these problems can be solved using the proposed methodology.
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Dobrovolskaya, O. G. "ANALYSIS OF EMERGENCY OPERATION OF WATER PIPELINES". Bulletin of Odessa State Academy of Civil Engineering and Architecture, nr 83 (4.06.2021): 122–29. http://dx.doi.org/10.31650/2415-377x-2021-83-122-129.

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In this work, the influence of individual sections of the water supply network on the dynamics of nodal heads in emergency operating modes is investigated. During accidents in the network sections, the dynamics of the head changes, the supply of water to the network decreases, areas with insufficient heads are formed. The subject of the analyzed stage of research is the influence of individual sections of the network on the location and size of areas with insufficient head. To determine the influence of individual sections of the network on head dynamics, methods of mathematical modeling of flow distribution in the water supply network, methods of hydraulic calculations of water supply networks were used. The results of studies of formation and change of areas with insufficient head taking into account emergency situations for networks with different structure and configuration are presented. The tasks to be performed by the flow management system at the network design stage are defined. Based on the results of the studies, the water supply conditions were evaluated during the formation of areas of insufficient pressure. Proposed algorithm consists of visualization of network structure, simulation of emergency situations, hydraulic calculations of network in normal and emergency operation modes, determination of actual head in network nodes, clarification of location of control nodes, calculation of required head of pumps in emergency operation mode. The proposed method allows you to determine the priority selection of network sections during its reconstruction and restoration. Modeling and analysis of pressure zones in the network allows you to change the number and location of pressure control units depending on the need. The proposed recommendations on flow management can be implemented in the work of utility dispatch services.
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Qin, Yinghong, Haifeng Yang, Zhiheng Deng i Jiang He. "Water Permeability of Pervious Concrete Is Dependent on the Applied Pressure and Testing Methods". Advances in Materials Science and Engineering 2015 (2015): 1–6. http://dx.doi.org/10.1155/2015/404136.

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Falling head method (FHM) and constant head method (CHM) are, respectively, used to test the water permeability of permeable concrete, using different water heads on the testing samples. The results indicate the apparent permeability of pervious concrete decreasing with the applied water head. The results also demonstrate the permeability measured from the FHM is lower than that from the CHM. The fundamental difference between the CHM and FHM is examined from the theory of fluid flowing through porous media. The testing results suggest that the water permeability of permeable concrete should be reported with the applied pressure and the associated testing method.
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Wester, T. E., A. D. Cherry, N. W. Pollock, J. J. Freiberger, M. J. Natoli, E. A. Schinazi, P. O. Doar i in. "Effects of head and body cooling on hemodynamics during immersed prone exercise at 1 ATA". Journal of Applied Physiology 106, nr 2 (luty 2009): 691–700. http://dx.doi.org/10.1152/japplphysiol.91237.2008.

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Immersion pulmonary edema (IPE) is a condition with sudden onset in divers and swimmers suspected to be due to pulmonary arterial or venous hypertension induced by exercise in cold water, although it does occur even with adequate thermal protection. We tested the hypothesis that cold head immersion could facilitate IPE via a reflex rise in pulmonary vascular pressure due solely to cooling of the head. Ten volunteers were instrumented with ECG and radial and pulmonary artery catheters and studied at 1 atm absolute (ATA) during dry and immersed rest and exercise in thermoneutral (29–31°C) and cold (18–20°C) water. A head tent varied the temperature of the water surrounding the head independently of the trunk and limbs. Heart rate, Fick cardiac output (CO), mean arterial pressure (MAP), mean pulmonary artery pressure (MPAP), pulmonary artery wedge pressure (PAWP), and central venous pressure (CVP) were measured. MPAP, PAWP, and CO were significantly higher in cold pool water ( P ≤ 0.004). Resting MPAP and PAWP values (means ± SD) were 20 ± 2.9/13 ± 3.9 (cold body/cold head), 21 ± 3.1/14 ± 5.2 (cold/warm), 14 ± 1.5/10 ± 2.2 (warm/warm), and 15 ± 1.6/10 ± 2.6 mmHg (warm/cold). Exercise values were higher; cold body immersion augmented the rise in MPAP during exercise. MAP increased during immersion, especially in cold water ( P < 0.0001). Except for a transient additive effect on MAP and MPAP during rapid head cooling, cold water on the head had no effect on vascular pressures. The results support a hemodynamic cause for IPE mediated in part by cooling of the trunk and extremities. This does not support the use of increased head insulation to prevent IPE.
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Boonyaphon, Korakot, Zhenglin Li, Geunyong Kim, Chae Seung Lim i Sung-Jin Kim. "Microfluidic sputum homogenizer driven by water-head pressure". Sensors and Actuators B: Chemical 277 (grudzień 2018): 431–36. http://dx.doi.org/10.1016/j.snb.2018.09.041.

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Cho, H., i G. H. de Rooij. "Pressure head distribution during unstable flow in relation to the formation and dissipation of fingers". Hydrology and Earth System Sciences 6, nr 4 (31.08.2002): 763–71. http://dx.doi.org/10.5194/hess-6-763-2002.

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Abstract. Wetting front instability creates a shallow induction zone from which fingers emerge that rapidly transport water and solutes downwards. How the induction zone affects finger location and spacing is unknown. In the moist subsoil, fingers may well dissipate because the finger tips no longer have to overcome the water entry value. Both flow regions were investigated in a two-dimensional chamber with a fine-over-coarse glass bead porous medium. A capillary fringe was created by upward wetting through capillary rise. Upon ponding with dye-coloured water, fingers emerged, propagated downward and diverged when reaching the capillary fringe. Microtensiometers were installed in the induction zone, the fingers, and in the capillary fringe. In the induction zone, a lateral sinusoidal pressure head developed within minutes. Only in one of two experiments could the observed pressure head pattern be satisfactorily reproduced by a steady-state model assuming uniform induction zone properties and uniform infiltration. Later, fingers emerged below the pressure head minima. The induction zone did not affect finger properties. The pressure head in the induction zone was determined by the depth of the finger tips. The water requirement of the fingers dictated the lateral pressure head gradients. The pressure heads in the capillary fringe supported the hypothesis that the flow stabilised and dissipated there. Keywords: fingered flow, wetting front instability, unsaturated flow, microtensiometers, induction zone, capillary fringe
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Rozprawy doktorskie na temat "WATER PRESSURE HEAD"

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Tran, Chi Thanh. "The Effective Convectivity Model for Simulation and Analysis of Melt Pool Heat Transfer in a Light Water Reactor Pressure Vessel Lower Head". Doctoral thesis, Stockholm : Division of Nuclear Power Safety, Royal Institute of Technology, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10671.

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van, Quang Pham. "Soil formation and soil moisture dynamics in agriculture fields in the Mekong Delta, Vietnam conceptual and numerical models". Licentiate thesis, KTH, Land and Water Resources Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10508.

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Previous studies of agricultural conditions in the Mekong Delta (MD) have identified soil compaction as an obstacle to sustainable production. A conceptual model for soil formation was presented to demonstrate the link between soil hydrology and plant response. Detailed studies of soil moisture dynamics in agricultural fields were conducted using a dynamic process-orientated model. Pressure head and water flow were simulated for three selected sites during a year for which empirical data were available. Daily meteorological data were used as dynamic input and measured pressure head was used to estimate parameter values that satisfied various acceptance criteria. The Generalised Likelihood Uncertainty Estimation (GLUE) approach was applied for calibration procedures with 10,000 runs, each run using random values within the chosen range of parameter values. To evaluate model performance and uncertainty estimation, re-sampling was carried out using coefficient of determination (R2) and mean error (ME) as the criteria. Correlations between parameters and R2 (and ME) and among parameters were also considered to analyse the relationship of the selected parameter set in response to increases/decreases in the acceptable simulations. The method was successful for two of the three sites, with many accepted simulations. For these sites, the uncertainty was reduced and it was possible to quantify the importance of the different parameters.

 

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Hasnain, Shahid. "Steady Periodic Water Waves Solutions Using Asymptotic Approach". Thesis, Linköpings universitet, Tillämpad matematik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-69421.

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The aim of this work is to study the relation between two invariants of water flow in a channel of finite depth. The first invariant is the height of the water wave and the second one is the flow force. We restrict ourselves to water waves of small amplitude. Using asymptotic technique together with the method of separation of variables, we construct all water waves of small amplitude which are parameterized by a small parameter. Then we demonstrate numerically that the flow force depends monotonically on the height.
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Johnson, Thomas G. "Heat Transfer in Brine Solutions at Supercritical Pressure". Ohio University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1439504843.

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竹井, 理絵, Rie TAKEI, 真貴 辻村, Maki TSUJIMURA, 丈子 高木 i Takeko TAKAGI. "異なる採取法による土壌水中の溶存無機イオン濃度の違い". 名古屋大学農学部付属演習林, 1998. http://hdl.handle.net/2237/8492.

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Sato, Alberto D. "Study of Upward-Facing Spray Cooling with Water at Atmospheric Pressure". Scholar Commons, 2006. http://scholarcommons.usf.edu/etd/3868.

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Spray cooling is a high heat removal technique which has been used widely in many industries, especially metallurgical, where the control of the temperatures of metals is an important factor to obtain the desired microstructure; and also in microelectronics where is very important to obtain high heat fluxes at relatively low surface temperatures. In this study, an open loop spray cooling system has been fabricated to provide an upward-facing spray over a 12 mm diameter test surface. A full cone spray nozzle was used to deliver deionized water to the test surface at five pressures (10, 15, 20, 25 and 30 psi), and at three different distances to the test surface (3, 7 and 12 mm). The volumetric flow rate at the surface used in the experiments depended on both the pressures and the distances. For a distance of 3 mm and 7 mm, the volumetric flow rate range from 336.6 to 627 ml/min while for 12 mm, the range was from 336.6 to 484.28 ml/min. Heat fluxes of 1.92 to 451 W/cm2, 2.1 to 417.3 W/cm2 and 1.9 to 409.5 W/cm2 for distances of 3, 7 and 12 mm respectively were registered at different input power levels. For all the three distances, the volumetric flow rate affects the heat flux, especially for 3 mm; and this effect decreases for higher distances. However, the distance between the nozzle and the test surface has little effect on the heat flux at low pressures but at higher pressures, the difference in heat flux is mainly due to the fact that part of the spray does not impinge the test surface.
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Fialová, Michaela. "Analýza hltnosti pojistného ventilu na napájecí vodě". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229746.

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In this thesis I review the sufficient flow capacity of the safety valve against high-pressure heater thermal pressurization in high-pressure feedwater heater on nuclear power Dukovany. I present basic possible cases of thermal pressurization both a high node heater, and the extended pressure unit in case of closure all power heads to steam generators.
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Kim, Sung Joong Ph D. Massachusetts Institute of Technology. "Subcooled flow boiling heat transfer and critical heat flux in water-based nanofluids at low pressure". Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/53274.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2009.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 285-290).
A nanofluid is a colloidal suspension of nano-scale particles in water, or other base fluids. Previous pool boiling studies have shown that nanofluids can improve the critical heat flux (CHF) by as much as 200%. In this study, subcooled flow boiling heat transfer and CHF experiments were performed with low concentrations of alumina, zinc oxide, and diamond nanoparticles in water (< 0.1 % by volume) at atmospheric pressure. It was found that for comparable test conditions the values of the nanofluid and water heat transfer coefficient (HTC) are similar (within ±20%). The HTC increased with mass flux and heat flux for water and nanofluids alike, as expected in flow boiling. The CHF tests were conducted at 0.1 MPa and at three different mass fluxes (1500, 2000, 2500 kg/m2s) under subcooled conditions. The maximum CHF enhancement was 53%, 53% and 38% for alumina, zinc oxide and diamond, respectively, always obtained at the highest mass flux. The measurement uncertainty of the CHF was less than 6.2%. A post-mortem analysis of the boiling surface reveals that its morphology is altered by deposition of the particles during nanofluids boiling. A confocal-microscopy-based examination of the test section revealed nanoparticles deposition not only changes the number of micro-cavities on the surface, but also the surface wettability. A simple model was used to estimate the ensuing nucleation site density changes, but no definitive correlation between the nucleation site density and the heat transfer coefficient data could be found.
(cont.) Wettability of the surface was substantially increased for heater coupons boiled in alumina and zinc oxide nanofluids, and such wettability increase seems to correlate reasonably well with the observed marked CHF enhancement for the respective nanofluids. Interpretation of the experimental data was conducted in light of the governing surface parameters and existing models. It was found that no single parameter could explain the observed HTC or CHF phenomena. The existing models were limited in studying the surface effects, suggesting that more accurate models incorporating surface effects need to be developed. Finally, the research activities performed in this thesis help identify the research gaps and indicate future research directions.
by Sung Joon Kim.
Ph.D.
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Hines, Amanda Meadows. "A non-equilibrium, pressure-pressure formulation for air-water two-phase flow and heat transport in porous media". Thesis, Mississippi State University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1548611.

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The detection of trace explosives in the subsurface is an active area of research for landmine detection. Understanding the air-water flow and heat transport phenomena in the subsurface plays an important role in improving chemical vapor detection. Implementing a finite element method that accurately captures water vapor transport in the vadose zone is still an open question. A non-equilibrium, pressure-pressure formulation has been implemented based on Smits, et al [22]. This implementation consists of four equations: a wetting phase (water) mass balance equation, a non-wetting phase (air) mass balance equation, a water vapor transport equation, and a heat transport equation. This work will compare two implementations, a fully coupled approach and an operator splitting approach for the water vapor and heat transport equations. The formulation of the methods will be presented and the methods will be tested using collected data from physical experiments.

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Mirmanto. "Single-phase flow and flow boiling of water in horizontal rectangular microchannels". Thesis, Brunel University, 2013. http://bura.brunel.ac.uk/handle/2438/7682.

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The current study is part of a long term experimental project devoted to investigating single-phase flow pressure drop and heat transfer, flow boiling pressure drop and heat transfer, flow boiling instability and flow visualization of de-ionized water flow in microchannels. The experimental facility was first designed and constructed by S. Gedupudi (2009) and in the present study; the experimental facility was upgraded by changing the piping and pre-heaters so as to accommodate the objectives of the research. These objectives include (i) modifying the test rig, to be used for conducting experiments in microchannels in single and two-phase flow boiling heat transfer, pressure drop and visualization, (ii) redesign metallic single microchannels using copper as the material. The purpose of the redesign is to provide microchannels with strong heaters, high insulation performance and with test sections easy to dismantle and reassemble, (iii) obtaining the effect of hydraulic diameter on single-phase flow, flow pattern, heat transfer and pressure drop, (iv) studying the effects of heat flux, mass flux,and vapour quality on flow pattern, flow boiling heat transfer and pressure drop, (v)comparing experimental results with existing correlations. However, the main focus in this present study is to investigate the effects of hydraulic diameter, heat flux, mass flux and vapour quality on flow pattern, flow boiling heat transfer coefficient and pressure drop. In addressing (iii) many possible reasons exist for the discrepancies between published results and conventional theory and for the scatter of data in published flow boiling heat transfer results: 1. Accuracy in measuring the dimensions of the test section, namely the width, depth and length and in the tested variables of temperature, pressure, heat flux and mass flux. 2. Variations in hydraulic diameter and geometry between different studies. 3. Differences in working fluids. 4. Effects of hydrodynamic and thermal flow development 5. Inner surface characteristics of the channels. Three different hydraulic diameters of copper microchannels were investigated: 0.438mm, 0.561 mm and 0.635 mm. For single-phase flow the experimental conditions included mass fluxes ranging from 278 – 5163 kg/m2 s, heat fluxes from 0 - 537 kW/m², and inlet temperatures of 30, 60 and 90°C. In the flow boiling experiments the conditions comprised of an inlet pressure of 125 kPa (abs), inlet temperature of 98°C (inlet sub-cooling of 7 K), mass fluxes ranging from 200 to 1100 kg/m²s, heat fluxes ranging from 0 to 793 kW/m² and qualities up to 0.41. All measurements were recorded after the system attained steady states. The single-phase fluid flow results showed that no deviation of friction factors was found from the three different hydraulic diameters. The effect of fluid temperature on friction factor was insignificant and the friction factors themselves were in reasonable agreement with developing flow theory. The typical flow patterns observed in all three test sections were bubbly, slug/confined churn and annular, however, based on the observation performed near the outlet, the bubbly flow was not detected. The effects of mass flow and hydraulic diameter on flow pattern for the three test sections investigated in the range of experimental conditions were not clear. The single-phase heat transfer results demonstrated that smaller test sections result in higher heat transfer coefficients. However, for heat transfer trends presented in the form of Nusselt number versus Reynolds number, the effect of hydraulic diameter was insignificant.The flow boiling experiments gave similar heat transfer results; they exhibited that the smaller hydraulic diameter channels resulted in higher heat transfer coefficients. The nucleate boiling mechanism was found for all three test sections, evidenced by the significant effect of heat flux on the local heat transfer coefficient. Moreover, the heat flux had a clear effect on average heat transfer coefficient for the 0.561 mm and 0.635mm test sections, whilst for the 0.438 mm test section, there was no discernible effect. At the same heat flux, increases in mass flux caused heat transfer coefficients to decrease. This could be due to the decrease of pressure inside the test section. When a higher mass flux was tested, the inlet pressure increased, and in reducing the inlet pressure to the original value, a decrease in system pressure resulted. Consequently, the outlet pressure and local pressure became lower. Existing flow pattern maps, flow boiling heat transfer and pressure drop correlations were compared with the experimental results obtained for all three test sections. The comparison showed that the flow pattern map proposed by Sobierska et al. (2006) was the most successful in predicting the experimental data. The local heat transfer coefficient data were compared with existing published correlations. The correlations of Yu et al. (2002), Qu and Mudawar (2003) and Li and Wu (2010) are found to predict the current local heat transfer coefficient better than other correlations tested. Pressure drop results showed that as the heat flux and mass flux were increased, the two-phase pressure drop increased too. These were due to the increase in bubble generations and the inertia momentum effect. As the channel was reduced, the twophase pressure drop increased because the pressure drop related inversely with the channel hydraulic diameter. The pressure and pressure drop fluctuations were indentified in this project, however, the maximum pressure fluctuation was found in the 0.438 mm channel whilst the minimum fluctuation was attained in the 0.561 mm channel. This indicated that the effect of decreasing in hydraulic diameter on pressure and pressure drop fluctuations is not clear and needs to be investigated further. The two-phase pressure drop data were compared with selected correlations. The Mishima and Hibiki (1996)’s correlation was found to predict the current two-phase pressure drop better than the other correlations examined in this study.
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Książki na temat "WATER PRESSURE HEAD"

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Agency, OECD Nuclear Energy, Pennsylvania State University i U.S. Nuclear Regulatory Commission. Office of Nuclear Regulatory Research. Division of Systems Technology., red. Proceedings of the OECD/CSNI Specialists Meeting on Boron Dilution Reactivity Transients: Held in State College, Pennsylvania, USA, October 18-20, 1995. Washington, DC: U.S. Nuclear Regulatory Commission, 1997.

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B, Oland C., Oak Ridge National Laboratory i U.S. Nuclear Regulatory Commission. Office of Nuclear Regulatory Research. Division of Engineering Technology., red. Marble Hill annealing demonstration evaluation. Washington, DC: The Commission, 1998.

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H, Cullen W., International Atomic Energy Agency, T͡Sentralʹnyĭ nauchno-issledovatelʹskiĭ institut tekhnologii mashinostroenii͡a (Soviet Union), U.S. Nuclear Regulatory Commission. Office of Nuclear Regulatory Research., Materials Engineering Associates i Argonne National Laboratory, red. Proceedings of the Third International Atomic Energy Agency Specialists' Meeting on Subcritical Crack Growth: Held at Moscow, USSR, May 14-17, 1990. Washington, D.C: The Commission, 1990.

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Ingrid, Chorus, red. Water, sanitation and health: Resolving conficts between drinking water demands and pressures from society's wastes : proceedings of the International Conference held in Bad Elster, Germany 24-28 November 1998. London: IWA Pub., 2000.

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Govindan, D. Numerical investigation of heat transfer in the vertical annulus between pressure tube and calandria tube of the advanced heavy water reactor. Mumbai: Bhabha Atomic Research Centre, 2008.

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The CHP Book of Amazing Experiments: You Can Do at Home (I Can Do That! Series). Niagra Falls, New York, USA: Hayes Publishing Ltd., 1985.

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Workshop on Gate Valve Pressure Locking and Thermal Binding, held at Marriott Hotel, New Orleans, LA, February 4, 1994. Washington, DC: U.S. Nuclear Regulatory Commission, 1995.

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Klein, Michael. Infrastructure. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198803720.003.0013.

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Infrastructure services in energy, transport, water, and telecommunications services underpin the wealth of modern nations. Yet inefficiencies abound. In developing nations hundreds of millions of people lack access to modern infrastructure services. Globally, as much as 40 percent of expenditures on infrastructure may constitute waste, equivalent to some 1 to 2 percent of global GDP. Natural monopoly features and sunk costs provide incentives for the parties to infrastructure ventures to play ransom games. Particularly in developing economies prices are often well below cost. Hence investors shy away and access remains limited. Government involvement in project choice and implementation may lead to ‘white elephants’ and mismanagement. Where head-to-head competition can be introduced, such as in modern telecommunications systems, the syndrome can be kept in check. Yet where such competition is not feasible, policymaking and inevitable price and quality regulation remain a challenge, requiring patient effort at arm’s-length from day-to-day political pressures.
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Proceedings of the Third International Atomic Energy Agency Specialists' Meeting on Subcritical Crack Growth: Held at Moscow, USSR, May 14-17, 1990. Washington, D.C: The Commission, 1990.

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Water, sanitation and health: Resolving conficts between drinking water demands and pressures from society's wastes : proceedings of the International Conference held in Bad Elster, Germany 24-28 November 1998. London: IWA Pub., 2000.

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Części książek na temat "WATER PRESSURE HEAD"

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Spellman, Frank R. "Force, Pressure, Head, Velocity Calculations". W Mathematics Manual for Water and Wastewater Treatment Plant Operators, 195–208. Wyd. 3. Boca Raton: CRC Press, 2023. http://dx.doi.org/10.1201/9781003354291-12.

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Nath, F., i S. Galbraith. "The Effect of Mannitol on Water Content of White Matter After Head Injury in Man". W Intracranial Pressure VI, 581–84. Berlin, Heidelberg: Springer Berlin Heidelberg, 1986. http://dx.doi.org/10.1007/978-3-642-70971-5_110.

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Kikuyama, K., Y. Hasegawa, G. Augusto, K. Nishibori i S. Nakamura. "The Swirling Inlet Flow Effects on the Pressure Recovery of a Low Head Water Turbine Draft Tube". W Hydraulic Machinery and Cavitation, 875–84. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-010-9385-9_89.

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Pauwels, Ine S., Jeffrey Tuhtan, Johan Coeck, David Buysse i Raf Baeyens. "Archimedes Screw—An Alternative for Safe Migration Through Turbines?" W Novel Developments for Sustainable Hydropower, 125–33. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-99138-8_11.

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AbstractFish passing downstream through hydraulic structures and turbines may risk dying or getting injured. Archimedes screw turbines are frequently considered more “fishfriendly” than conventional turbines. However, to date only a handful of studies assess the impact of Archimedes screws. Within the FIThydro project, we investigated injury and mortality on 2700 bream, roach and eel, including passive barotrauma sensors passing a large Archimedes hydrodynamic screw (10 m head, 22 m length) on three rotational speeds of 30, 40 and 48 Hz. The sensors measured total water pressure, linear acceleration, rotation rate, magnetic field intensity and absolute orientation. They indicated that passage is a chaotic event, and that barotrauma-related injury and mortality are indeed unlikely. Nonetheless, substantial mortality of fish was observed, specifically for bream (42%) and roach (18%) but not for eel (1%). No straightforward relation was found between rotational speeds and fish injury and mortality. The study indicates generally lower mortality and injury rates compared to conventional turbine types. However, fish can still get heavily injured or die, depending on the fish species. Therefore, we stress the need for further studies on Archimedes screws to identify the causes of the observed species-specific injury and mortality rates.
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Liu, Benqin, Jin Yang, Yue Huang i Lei Wang. "Hydraulic Research on Filling and Emptying System of Water-Saving Ship Lock for Navigation-Power Junction in Mountainous River". W Lecture Notes in Civil Engineering, 1492–501. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-6138-0_132.

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AbstractUsually the ship lock has the characteristics of high water head and large variation of navigable water level in mountainous area. It is suitable to construct the water-saving ship lock, which can not only save the water consumption but also reduce the working head of each stage. Therefore, it is also beneficial to solve the hydraulic problems of high head ship lock. Taking Baise ship lock as an example of ship locks for navigation-power junctions in mountainous river, we studied the water saving layout scheme and suggested that a high water saving pool and a low one should be set on both sides of the lock chamber. And each pool adopts a new type of trapezoidal transverse section in order to make full use of the topographic conditions of the project and reduce the excavation volume. The water level classification of water-saving ship lock is calculated and analyzed. The elevations of the water saving pools are determined. The layout of the filling and emptying system of the water-saving ship lock is put forward. The hydraulic characteristic indexes, the pressures of the culverts near the valves and the ship berthing conditions in lock chamber under different operating conditions of the water-saving ship lock are obtained through physical model research. Furthermore, the opening and closing modes of the valves are recommended. The results show that the water saving scheme of Baise ship lock is reasonable and feasible in hydraulics.
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Zhao, Zixiang, Zhongdi Duan, Hongxiang Xue, Yuchao Yuan i Shiwen Liu. "Effects of Inlet Conditions on the Two-Phase Flow Water Hammer Transients in Elastic Tube". W Springer Proceedings in Physics, 955–72. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-1023-6_81.

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AbstractTwo-phase flow water hammer events occur in the pipelines of the nuclear power systems and lead to transient and violent pressure shock to tube structures. For the sake of operation safety, the occurrence and severity of the two-phase water hammer should be carefully assessed. This paper presents a parameter analysis of the inlet conditions on the two-phase flow water hammer transients, with considering the elastic effect of the tube walls. A numerical model is established for the vapor-liquid two-phase flow based on the two-fluid six-equation modelling approach, with incorporating correlations and criterions for two-phase flow regime, interfacial interactions and heat transfer. The governing equations are transformed to matrix form expressed by characteristic variables, and solved using the splitting operator method and the total variation diminishing scheme. The accuracy of the model is verified against the experimental data in open literature. Then, the model is applied to investigate the effect of inlet velocity and inlet water temperature on the two-phase flow water hammer transients. The simulation results show that the increase of inlet velocity increases the pressure peak values and brings forward the onset of water hammer, and the increase of inlet temperature decreases the pressure shock. A comparison of the water hammer results between the elastic tube and rigid tube is further presented, and the effect of the elastic modulus on the water hammer is analyzed. The results also show that the pressure peak is largely affected by the tube diameter.
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Vujisic, Lj B., I. Catton i N. H. Afgan. "Air-Water Two-Phase Flow Pressure Drop in Large Scale Porous Media". W Convective Heat and Mass Transfer in Porous Media, 773–89. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3220-6_26.

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Wang, Zhiwei, Yanping He, Zhongdi Duan, Chao Huang i Shiwen Liu. "Direct Contact Condensation Characteristics of Steam Injection into Cold-Water Pipe Under Rolling Condition". W Springer Proceedings in Physics, 753–63. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-1023-6_65.

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AbstractDirect contact condensation (DCC) is widely occurred in nuclear power systems and leads to undesired phenomena such as condensation-induced water hammer. For ocean nuclear power ships, DCC is inevitable in the passive heat removal system and influenced by sea conditions. In this paper, the characteristics of DCC under rolling conditions are analyzed. The numerical model of DCC is established based on computational fluid dynamics approach. The VOF model, SST k–ω turbulence model and the additional inertia force model are incorporated to describe the liquid-gas two-phase flow under the rolling motion. The condensation model based on surface renewal theory (SRT) is used to simulate steam-water DCC phenomenon. The simulation results are compared with the experimental data and show reasonable agreement. The effects of rolling motion on DCC for steam injection into a horizontal pipe filled with cold water are numerically investigated. The results show that the additional inertial forces and the average condensation rate increase with the increase of the rolling angle and frequency. The reverse flow of the seawater induced by rolling motion leads to the accumulation of the steam at the lower part of the pipe, resulting in a large pressure pulse. With the increase of rolling angle and frequency, the pressure pulse induced by DCC increases.
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Zhang, Xueyan, Yixuan Zhang, Ye Yang, Chengcheng Deng i Jun Yang. "Uncertainty Analysis and Sensitivity Evaluation of a Main Steam Line Break Accident on an Advanced PWR". W Springer Proceedings in Physics, 327–41. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-1023-6_30.

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AbstractA RELAP5 input model was established for a scaled-up facility simulating China's Advanced Passive Water Reactor with passive safety features. The simulation was performed to reproduce a Main Steam Line Break (MSLB) scenario at steam line connected to one Steam Generator. The figure of merit selected in this accident scenario includes the maximum containment pressure, mass and energy release to containment. Driving factors of this response function include Passive Residue Heat Removal material thermal conductivity, Pressurizer temperature, and broken steam line temperature.To achieve an adequately justified safety margin using a Best Estimate Plus Uncertainty analysis, dominant phenomena were selected from a reference Phenomenon Identification and Ranking Table. The calculation results were compared with the available reference data of similar Generation III Passive Water Reactor to assess the code's capability to predict the MSLB phenomena. The DAKOTA toolkit is used to drive both parameter sensitivity analysis and uncertainty propagation. The 95/95 uncertainty bands of key output parameters were obtained using the Wilks’ statistical methods.Compared with the reference data, the simulation results partially confirmed the stability and repeatability of the code model for initial and boundary condition perturbations. The uncertainty bands of important output parameters were demonstrated. The results indicated that the maximum containment pressure value was below the safety limit, and the passive safety system can mitigate the consequence of the MSLB. The mass and energy released into the containment were assessed according to the containment design.The parameter sensitivity analysis was performed with 34 input parameters, and the results were evaluated by Spearman's Simple Rank Correlation Coefficients.
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Schumann, Jan-Erik, Markus Fertig, Volker Hannemann, Thino Eggers i Klaus Hannemann. "Numerical Investigation of Space Launch Vehicle Base Flows with Hot Plumes". W Notes on Numerical Fluid Mechanics and Multidisciplinary Design, 179–91. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-53847-7_11.

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Abstract The flow field around generic space launch vehicles with hot exhaust plumes is investigated numerically. Reynolds-Averaged Navier-Stokes (RANS) simulations are thermally coupled to a structure solver to allow determination of heat fluxes into and temperatures in the model structure. The obtained wall temperatures are used to accurately investigate the mechanical and thermal loads using Improved Delayed Detached Eddy Simulations (IDDES) as well as RANS. The investigated configurations feature cases both with cold air and hot hydrogen/ water vapour plumes as well as cold and hot wall temperatures. It is found that the presence of a hot plume increases the size of the recirculation region and changes the pressure distribution on the nozzle structure and thus the loads experienced by the vehicle. The same effect is observed when increasing the wall temperatures. Both RANS and IDDES approaches predict the qualitative changes between the configurations, but the reattachment location predicted by IDDES is up to 7% further upstream than that predicted by RANS. Additionally, the heat flux distribution along the nozzle and base surface is analysed and shows significant discrepancies between RANS and IDDES, especially on the nozzle surface and in the base corner.
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Streszczenia konferencji na temat "WATER PRESSURE HEAD"

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Saldarriaga, Juan G., Felipe S. Contreras i Augusto H. Sisa. "Methodology for the Determination of Optimal Water Head Pressure in Water Distribution Network". W World Water and Environmental Resources Congress 2003. Reston, VA: American Society of Civil Engineers, 2003. http://dx.doi.org/10.1061/40685(2003)117.

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Shaazizov, F. "Hydraulic head losses on pressure pipelines of hydropower plants". W THE THIRD INTERNATIONAL SCIENTIFIC CONFERENCE CONSTRUCTION MECHANICS, HYDRAULICS AND WATER RESOURCES ENGINEERING (CONMECHYDRO 2021 AS). AIP Publishing, 2023. http://dx.doi.org/10.1063/5.0113233.

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Shi, Jin, Wen Liu i Xin Cheng. "Failure Analysis of a Cracked Stainless-Steel Steam-Water Separator". W ASME 2021 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/pvp2021-62032.

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Abstract Currently, austenitic stainless steel has been widely used for the pressure boundary, including reactors, separators and storage tanks serviced in energy, petrochemical, chemical and food industries in view of its inherent corrosion resistance. However, the corrosion resistance may deteriorate under some circumstances such as field welding and inappropriate post-weld heat treatment. A steam-water separator serviced in a power plant was found cracking and a large amount of steam leaked outside. The cracking was located in the heat-affected zone (HAZ) of the joint on the head side of the pressure vessel. The material of the head was SUS 304 austenite stainless steel. Failure analysis was conducted to investigate the cause of cracking. The testing and measurement included chemical composition analysis, metallographic examination, fracture surface observation and deposit elements analysis. Results showed that the cracking was intergranular and stress corrosion cracking (SCC) was the primary cause of failure. During the fabrication of the separator, the HAZ of the joint was overheated by the thermal input of welding. Brittle carbides such as M23C6 precipitating at the grain boundary, resulted in a narrow belt lack of chromium nearby known as sensitization. The corrosion resistance of the austenite stainless-steel decreased obviously there, and cracking failure occurred rapidly under tensile stress. The influencing factors discussed in this paper mainly focused on material performance, post-weld heat treatment, and corrosivity of medium. Austenitic stainless steel containing stabilizing elements or with low C content was recommended for the new vessel design in order to avoid similar cracking failure.
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Bilanin, Alan J., Andrew E. Kaufman i Warren J. Bilanin. "Recapturing Net Positive Suction Head Margins in Boiling Water Reactor Emergency Core Cooling Systems". W ASME 2017 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/pvp2017-66141.

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Boiling Water Reactor pressure suppression pools have stringent housekeeping requirements, as well as restrictions on amounts and types of insulation and debris that can be present in the containment, to guarantee that suction strainers that allow cooling water to be supplied to the reactor during a Loss of Coolant Accident remain operational. By introducing “good debris” into the cooling water, many of these requirements/restrictions can be relaxed without sacrificing operational readiness of the cooling system.
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Liu, Zhelin, John Michael Harris, Jichuan Liu, Dong Han i Lei Liu. "Traditional Versus New Technology Boiler Drum Water Level Instruments". W ASME 2016 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/pvp2016-63203.

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The art and science of boiler drum water level measurement has long been the source of questionable results. A low-tech examination of the boiler drum reveals where the drum level has been controlling — there is a water mark inside the drum. The problem is obvious; the mark in the drum and that in the control system do not agree. The level is off by a wide margin. This paper seeks to explain how poor assumptions are the source of the error. Then two design approaches are considered to eliminate the sources of error. Consider that boiler drum water is not saturated; feedwater entering from the economizer is below saturation. Also consider the constant head chamber. Typically, the reference leg is considered to be at ambient temperature, but it is really a gradient starting at near drum temperature. The effect of these two poor assumptions is a relatively large error such that the true level is different from indicated level. Once this situation is understood, it is possible to redesign instruments which take the actual situation into account. One such instrument is nearly the same as the original DP-type instrument, but the constant head chamber is located inside the drum. This design change deals with both errors. It eliminates the differences in temperature and density between the constant head leg and the water inside the drum. It also exposes the constant head leg to the exact same temperature as the boiler water, thus eliminating the need for complicated (and incorrect) formulae to compensate for the differences in density. A second design approach is to “steam jacket” an instrument located outside the drum, thus eliminating the differences in temperature and density. This is an appropriate way to deal with the Conductivity Probe and the Boiler Water gauge glass. By steam jacketing these instruments, we can make the water temperature between the indicator and the drum almost the same.
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Valderrama, Juan Guillermo Saldarriaga, Daniel Rodríguez Amaya i Manuel Antonio Serna Rodríguez. "Experience in the Application of Methodology for Determination of Optimal Water Head Pressure in Water Distribution Networks". W Eighth Annual Water Distribution Systems Analysis Symposium (WDSA). Reston, VA: American Society of Civil Engineers, 2008. http://dx.doi.org/10.1061/40941(247)86.

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Marlette, Stephen, i Stan Bovid. "Evaluation of Laser Peening for Mitigation of Primary Water Stress Corrosion Cracking in Pressurized Water Reactors". W ASME 2019 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/pvp2019-93361.

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Abstract For several decades pressurized water reactors have experienced Primary Water Stress Corrosion Cracking (PWSCC) within Alloy 600 components and welds. The nuclear industry has developed several methods for mitigation of PWSCC to prevent costly repairs to pressurized water reactor (PWR) components including surface stress improvement by peening. Laser shock peening (LSP) is one method to effectively place the surface of a PWSCC susceptible component into compression and significantly reduce the potential for crack initiation during future operation. The Material Reliability Program (MRP) has issued MRP-335, which provides guidelines for effective mitigation of reactor vessel heads and nozzles constructed of Alloy 600 material. In addition, ASME Code Case N-729-6 provides performance requirements for peening processes applied to reactor vessel head penetrations in order to prevent degradation and take advantage of inspection relief, which will reduce operating costs for nuclear plants. LSP Technologies, Inc. (LSPT) has developed and utilized a proprietary LSP system called the Procudo® 200 Laser Peening System. System specifications are laser energy of 10 J, pulse width of 20 ns, and repetition rate of 20 Hz. Scalable processing intensity is provided through automated focusing optics control. For the presented work, power densities of 4 to 9.5 GW/cm2 and spot sizes of nominally 2 mm were selected. This system has been used effectively in many non-nuclear industries including aerospace, power generation, automotive, and oil and gas. The Procudo® 200 Laser Peening System will be used to process reactor vessel heads in the United States for mitigation of PWSCC. The Procudo® 200 Laser Peening System is a versatile and portable system that can be deployed in many variations. This paper presents test results used to evaluate the effectiveness of the Procudo® 200 Laser Peening System on Alloy 600 material and welds. As a part of the qualification process, testing was performed to demonstrate compliance with industry requirements. The test results include surface stress measurements on laser peened Alloy 600, and Alloy 182 coupons using x-ray diffraction (XRD) and crack compliance (slitting) stress measurement techniques. The test results are compared to stress criteria developed based on the performance requirements documented in MRP-335 and Code Case N-729-6. Other test results include surface roughness measurements and percent of cold work induced by the peening process. The test results demonstrate the ability of the LSP process to induce the level and depth of compression required for mitigation of PWSCC and that the process does not result in adverse conditions within the material.
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Remic, Joseph M., Neal D. Johnston, George J. Demetri i David H. Roarty. "Methodology for Reactor Vessel Head Drop Accident Analysis". W ASME 2008 Pressure Vessels and Piping Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/pvp2008-61686.

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Nuclear power plants are required to evaluate the risks associated with a potential accident in which the reactor vessel closure head is dropped onto a reactor with fuel installed. This is done as part of an overall effort to safely control the movement of heavy loads in a nuclear facility per NUREG-0612 [1]. In some cases, this requires that an analysis be done of the potential accident to confirm no damage to fuel would occur. This paper provides a methodology for such analysis, along with the basis for the methodology, for a typical pressurized water reactor design. The methodology uses nonlinear, dynamic transient finite element analysis to analyze the event. An example of typical results and acceptance criteria is provided.
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Forsyth, David R., Pat L. Strauch i Paul J. Kreitman. "The Impact of a Reactor Vessel Upper Head Temperature Reduction Program on Cracking Potential and Inspection of Alloy 600 Closure Head Penetrations". W ASME/JSME 2004 Pressure Vessels and Piping Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/pvp2004-2554.

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Primary water stress corrosion cracking (PWSCC) of Alloy 600 reactor pressure vessel closure head penetrations is very sensitive to a number of material and service parameters. Plant experience to date does indicate that time at elevated temperatures is a strong indicator of cracking potential. As a result, lowering temperatures can be an effective way to increase the time for crack initiation, to reduce the rate of crack propagation, to reduce the number of required closure head penetration inspections and to extend the useful life of an existing closure head or a replacement closure head. In this paper, the reactor coolant flow paths into and out of the upper head region of a pressurized water reactor are presented along with the field modifications performed to reduce the upper head region temperature. These modifications are known as an Upper Head Temperature Reduction (UHTR) program. In addition, a simplified model for assessing the impact of temperatures on the potential for crack initiation and crack growth of Alloy 600 closure head penetrations is presented. The impact of a UHTR program and the resulting reduced temperature on crack initiation, as measured by effective degradation years (EDYs), and on crack growth is also discussed. Actual UHTR implementation designs and recent Westinghouse UHTR field modification experiences are also presented.
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Hinnant, Chris. "Fatigue Testing of Welded Flat Head Pressure Vessel Joints". W ASME 2007 Pressure Vessels and Piping Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/pvp2007-26622.

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Experimental results for the fatigue testing of several welded flat head geometries are reported. These tests are similar to those previously reported by Hinnant (2006) [1] and focus on the fatigue behavior of full penetration welds with cover fillet welds. Fatigue calculations according to several fatigue design methods are compared against the experimental results, as are the mean fatigue curves of several of the design methods. Of particular interest for these new tests is the effect of plate thickness, testing environment, and geometric effects. Nominal plate thickness values ranging from 0.0625" (1.59 mm) to 0.1875" (4.76 mm) have been tested and correlated. Four additional fatigue tests were conducted using air to determine if previous testing in room temperature tap water resulted in decreased fatigue life.
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Raporty organizacyjne na temat "WATER PRESSURE HEAD"

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Haslett, G. A., G. R. Corbett i D. A. Young. An investigation into the effect of varying water pressure and flow rates upon the release of airborne respirable dust by a DOSCO MKIIB roadheader equipped with a water jet assisted cutting head. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1986. http://dx.doi.org/10.4095/304884.

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Haslett, G. A., G. R. Corbett i D. A. Young. An investigation into the effect of varying water pressure and flow rates upon the release of airborne respirable dust by a DOSCO MKIIB roadheader equipped with a water jet assisted cutting head. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1986. http://dx.doi.org/10.4095/304912.

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Warrick, Arthur, Uri Shani, Dani Or i Muluneh Yitayew. In situ Evaluation of Unsaturated Hydraulic Properties Using Subsurface Points. United States Department of Agriculture, październik 1999. http://dx.doi.org/10.32747/1999.7570566.bard.

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The primary information for accurately predicting water and solute movement and their impact on water quality is the characterization of soil hydraulic properties. This project was designed to develop methods for rapid and reliable estimates of unsaturated hydraulic properties of the soil. Particularly, in situ methodology is put forth, based on subsurface point sources. Devices were designed to allow introduction of water in subsurface settings at constant negative heads. The ability to operate at a negative head allows a direct method of finding unsaturated soil properties and a mechanism for eliminating extremely rapid preferential flow from the slow matrix flow. The project included field, laboratory and modeling components. By coupling the measurements and the modeling together, a wider range of designs can be examined, while at the same time realistic performance is assured. The developed methodology greatly expands the possibilities for evaluating hydraulic properties in place, especially for measurements in undisturbed soil within plant rooting zones. The objectives of the project were (i) To develop methods for obtaining rapid and reliable estimates of unsaturated hydraulic properties in situ, based on water distribution from subsurface point sources. These can be operated with a constant flow or at a constant head; (ii) To develop methods for distinguishing between matrix and preferential flow using cavities/permeameters under tension; (iii) To evaluate auxiliary measurements such as soil water content or tensions near the operating cavities to improve reliability of results; and (iv: To develop numerical and analytical models for obtaining soil hydraulic properties based on measurements from buried-cavity sources and the auxiliary measurements. The project began in July 1995 and was terminated in November 1998. All of the objectives were pursued. Three new subsurface point sources were designed and tested and two old types were also used. Two of the three new designs used a nylon cloth membrane (30 mm) arranged in a cylindrical geometry and operating at a negative water pressure (tension). A separate bladder arrangement allowed inflation under a positive pressure to maintain contact between the membrane and the soil cavity. The third new design used porous stainless steel (0.5 and 5 mm) arranged in six segments, each with its own water inlet, assembled to form a cylindrical supply surface when inflated in a borehole. The "old" types included an "off-the-shelf" porous cup as well as measurements from a subsurface drip emitter in a small subsurface cavity. Reasonable measurements were made with all systems. Sustained use of the cloth membrane devices were difficult because of leaks and plugging problems. All of the devices require careful consideration to assure contact with the soil system. Steady flow was established which simplified the analysis (except for the drip emitter which used a transient analysis).
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Fukuda, K., M. Shiotsu i A. Sakurai. Transient pool boiling heat transfer due to increasing heat inputs in subcooled water at high pressures. Office of Scientific and Technical Information (OSTI), wrzesień 1995. http://dx.doi.org/10.2172/107012.

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Shen, Bo. Literature Review of Heat Transfer and Pressure Drop Correlations for HFO Blends in Water Heating Application. Office of Scientific and Technical Information (OSTI), wrzesień 2019. http://dx.doi.org/10.2172/1564210.

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Lever, James, Austin Lines, Susan Taylor, Garrett Hoch, Emily Asenath-Smith i Devinder Sodhi. Revisiting mechanics of ice–skate friction : from experiments at a skating rink to a unified hypothesis. Engineer Research and Development Center (U.S.), grudzień 2021. http://dx.doi.org/10.21079/11681/42642.

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The mechanics underlying ice–skate friction remain uncertain despite over a century of study. In the 1930s, the theory of self-lubrication from frictional heat supplanted an earlier hypothesis that pressure melting governed skate friction. More recently, researchers have suggested that a layer of abraded wear particles or the presence of quasi-liquid molecular layers on the surface of ice could account for its slipperiness. Here, we assess the dominant hypotheses proposed to govern ice– skate friction and describe experiments conducted in an indoor skating rink aimed to provide observations to test these hypotheses. Our results indicate that the brittle failure of ice under rapid compression plays a strong role. Our observations did not confirm the presence of full contact water films and are more consistent with the presence of lubricating ice-rich slurries at discontinuous high-pressure zones (HPZs). The presence of ice-rich slurries supporting skates through HPZs merges pressure-melting, abrasion and lubricating films as a unified hypothesis for why skates are so slippery across broad ranges of speeds, temperatures and normal loads. We suggest tribometer experiments to overcome the difficulties of investigating these processes during actual skating trials.
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Johra, Hicham. Performance overview of caloric heat pumps: magnetocaloric, elastocaloric, electrocaloric and barocaloric systems. Department of the Built Environment, Aalborg University, styczeń 2022. http://dx.doi.org/10.54337/aau467469997.

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Heat pumps are an excellent solution to supply heating and cooling for indoor space conditioning and domestic hot water production. Conventional heat pumps are typically electrically driven and operate with a vapour-compression thermodynamic cycle of refrigerant fluid to transfer heat from a cold source to a warmer sink. This mature technology is cost-effective and achieves appreciable coefficients of performance (COP). The heat pump market demand is driven up by the urge to improve the energy efficiency of building heating systems coupled with the increase of global cooling needs for air-conditioning. Unfortunately, the refrigerants used in current conventional heat pumps can have a large greenhouse or ozone-depletion effect. Alternative gaseous refrigerants have been identified but they present some issues regarding toxicity, flammability, explosivity, low energy efficiency or high cost. However, several non-vapour-compression heat pump technologies have been invented and could be promising alternatives to conventional systems, with potential for higher COP and without the aforementioned refrigerant drawbacks. Among those, the systems based on the so-called “caloric effects” of solid-state refrigerants are gaining large attention. These caloric effects are characterized by a phase transition varying entropy in the material, resulting in a large adiabatic temperature change. This phase transition is induced by a variation of a specific external field applied to the solid refrigerant. Therefore, the magnetocaloric, elastocaloric, electrocaloric and barocaloric effects are adiabatic temperature changes in specific materials when varying the magnetic field, uniaxial mechanical stress, electrical field or hydrostatic pressure, respectively. Heat pump cycle can be built from these caloric effects and several heating/cooling prototypes were developed and tested over the last few decades. Although not a mature technology yet, some of these caloric systems are well suited to become new efficient and sustainable solutions for indoor space conditioning and domestic hot water production. This technical report (and the paper to which this report is supplementary materials) aims to raise awareness in the building community about these innovative caloric systems. It sheds some light on the recent progress in that field and compares the performance of caloric systems with that of conventional vapour-compression heat pumps for building applications.
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Bucci, Matteo, Jee H. Seong, Jdacopo Buongiorno, Andrew Richenderfer i A. Kossolapov. IR-thermography-based investigation of critical heat flux in subcooled flow boiling of water at atmospheric and high pressure conditions. Office of Scientific and Technical Information (OSTI), listopad 2017. http://dx.doi.org/10.2172/1409276.

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Yu, W., D. M. France i J. L. Routbort. Pressure drop, heat transfer, critical heat flux, and flow stability of two-phase flow boiling of water and ethylene glycol/water mixtures - final report for project "Efficent cooling in engines with nucleate boiling.". Office of Scientific and Technical Information (OSTI), styczeń 2011. http://dx.doi.org/10.2172/1009796.

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Leis i Brust. L51665 Hydrotest Strategies for Gas Transmission Pipelines Based on Ductile-Flaw-Growth Considerations. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), lipiec 1992. http://dx.doi.org/10.55274/r0010296.

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Historically safe operation of thousands of miles of gas- transmission pipeline underscores the merits of hydrotesting. The hydrotest is applied to remove defects, which might exist in the line and could be critical in subsequent service. The hydrotest involves a proof pressurization that is designed to remove defects that could otherwise become critical in service by failing these defects during the time the line is held at the over-pressure. Water is used as the pressurization media to avoid the potential for running fracture, which is possible in cases where defects become critical during the test when using more compressible media (e.g., gases). Hydrotesting is not the only means to ensure defects that could become critical in subsequent service are identified and removed from a line. For example, inline inspection (ILI) procedures are available that permit the identification of specific types of defects, such as corrosion. But because not all lines can be inspected with ILI tools and the need to find types of defects that are not currently detected by inline procedures, hydrotesting remains the method of choice in the USA for natural gas transmission lines. The objective of this study was to determine the growth of various flaw sizes as a result of having been subjected to combinations of test pressures and hold times and to assess the subsequent serviceability of pipelines containing those flaws in gas-transmission service. The purpose of the flaw-growth calculations is to define hydrotest procedures for gas-transmission pipelines that remove flaws that could become critical in service while minimizing the growth of any remaining flaws. This report is the fourth in a series of topical reports dealing with quasi-static ductile flaw growth in pipelines, such as can occur in a hydrotest. Prior reports presented relevant material properties, the theoretical analysis, and the model development and validation. This report presents the results and analysis of an extensive parametric study of ductile flaw growth as a function of maximum test pressure, hold time, flaw geometry, and strength and toughness of the pipe steel representative of submerged-arc welded pipe in grades from X52 through X70 with a yield-to-ultimate ratio less than 0.90.
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