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Water Distribution
Published in Samuel C. Sugarman, HVAC Fundamentals, 2020
The refrigerant vapor from the evaporator is drawn into the low pressure area created by controlling the temperature and concentration of the refrigerant-absorbent solution (i.e., the higher the concentration and the lower the temperature of the lithium bromide and refrigerant water solution the lower its vapor pressure).
An analysis of the influence of affordable housing system on price
Published in Dawei Zheng, Industrial, Mechanical and Manufacturing Science, 2015
(1) the pressure changing trend inside the centrifugal pump impeller: the pressure gradually reduces after entering from the entrance and then gradually rises towards export volute, and there is a low pressure area in the later place of the inlet where the pressure is lower than the saturated vapor pressure under normal temperature, which is one of the important reasons for the centrifugal pump to produce cavitation. Most of the kinetic energy is converted into pressure energy in the volute area, and there is a higher discharge pressure at the exit.
Isotopic characterization of waters across chile
Published in Diego A. Rivera, Alex Godoy-Faundez, Mario Lillo-Saavedra, Andean Hydrology, 2018
R. Sánchez-Murillo, E. Aguirre-Dueñas, M. Gallardo-Amestica, P. Moya-Vega, C. Birkel, G. Esquivel-Hernández, J. Boll
The western slope of the Andes Cordillera is an exceptional case, because precipitation at higher elevation is controlled by continental air mass trajectories from the Atlantic Ocean, which travel through a wide range of biomes from the Amazon Basin to the Patagonia region, resulting in depleted precipitation. In contrast, in the coastal and central lowland regions, precipitation is mainly governed by the southeastern Pacific Ocean dynamics, resulting in enriched precipitation (Aravena et al., 1999). The combination of both processes is reflected in large apparent orographic effects, but also in remarkable spatial isotopic differences. Figure 9.63 shows a gridded mean annual δ18Ο (%) below ~ 20° S for South America according to Bowen and Revenaugh (2003). Although, this precipitation isoscape captures the isotopic difference within the western and eastern slopes of the Andes Cordillera, the relative magnitude of the isotopic composition appears to be strongly biased by the temperature effect, which is based solely on latitude and altitude estimations (e.g., δ18Ορ= a/Lat J2+ b/LatJ + cAltx; Bowen and Revenaugh, 2003), without taking into consideration the strong influence of the southeastern Pacific anticyclone (high pressure area) and circumpolar low pressure area from the Antarctic Sea. The latter is represented in the HYSPLIT air mass back trajectories (Fig. 9.64). During the wettest months, precipitation at La Serena and Santiago mainly originated from within the southeastern Pacific Ocean, whereas a strong Antarctic Sea influence was observed at Puerto Montt and Punta Arenas. Figure 9.65 shows representative isotopic data in different hydrological components. Although, historical isotopic studies in Chile have been highly concentrated in the northern region, the available data serve as a fundamental reference. As expected, ice coring data at high elevation sites presented the most depleted compositions but in a similar range of modern precipitation (Fig. 9.59). In the northern region, groundwater and surface water exhibited strong secondary evaporation processes; however, the isotopic spectrum (Fig. 9.65) also highlighted the relevance of spring recharge at high elevations in several locations in the western slope of the Andes Cordillera.
Thermal effect on cavitation characteristics of a hydraulic torque converter
Published in Numerical Heat Transfer, Part A: Applications, 2022
Meng Guo, Cheng Liu, Jiahua Zhang, Shiqi Liu, Qingdong Yan, Boo Cheong Khoo
The absolute pressure, oil mass flow, and vapor mass flow in a meridional surface are shown in Figure 13. The pressure distribution was relatively uniform at low temperature, and the overall pressure was lower in the stator than the other two components. As the temperature increased, high-pressure region began to appear on the outer ring of the turbine, and low-pressure region emerged in the stator domain. Moreover, the high-pressure/low-pressure area expanded and the pressure distribution gradient went up with the increase of temperature. We can then conclude from Figure 13 that both the oil and vapor mass flow rate increases with an increased temperature, and both the oil velocity peak and the vapor velocity peak occurred near the inlet inside the stator at high temperatures, overall resulting in intense cavitation in the corresponding area.
Aerodynamic characteristics of the evacuated tube maglev train considering the suspension gap
Published in International Journal of Rail Transportation, 2022
Peng Zhou, Deng Qin, Jiye Zhang, Tian Li
In this study, a simplified 3-D ETMT is used to simulate the motion in the tube by the dynamic mesh method. Based on the flow characteristics, the actual physical properties of the air in the tube are considered. By numerical simulation, the influence of different suspension gap on the aerodynamic characteristics is studied in detail. Some main conclusions can be summarized as follows: The viscosity has almost no contribution to lift and the contribution induced by pressure difference to the whole drag is more than 90%. The gap increase contributes to increasing the drag and lift of TC and decreasing the HC drag.The suspension gap mainly affects the pressure and temperature distributions at the train bottom. The gap decrease is helpful to enlarge the low-pressure area on the HC bottom and the high-temperature area on the train due to the ‘ground effect’. Given the typical streamwise symmetry line, the gap decrease has little effect on pressure but increases temperature sharply.Based on the change of pressure or temperature on the symmetry line of tube, the distribution space of the pressure or temperature can be divided into five sections. The gap decrease has little effect on the tube but is helpful to shorten the formation time of NSW. More importantly, the gap decrease is advantageous to enhancing the ‘ground effect’ and shock effect on the ground.There is a pair of counter-rotating vortexes near the TC nose tip. As the gap decreases, the downwash effect induced by the vortex is improved in wake.