Facing the contradiction of water scarcity and water wastage in most cities of China, this study aims at probing into the factors influencing water-use efficiency and assessing water-saving potential by adopting press...Facing the contradiction of water scarcity and water wastage in most cities of China, this study aims at probing into the factors influencing water-use efficiency and assessing water-saving potential by adopting pressure control measures based on field survey conducted in 23 high-rise buildings in Suqian, China and laboratory tests. Results showed that per capita water consumption (PCWC) exceeding water consumption norms is common in these buildings. The hourly water consumption variation law is quite different among different types of buildings. These differences should be considered in designing building water supply systems to lower water and energy consumption. On the basis of correlation analysis, the order of factors influencing the PCWC follows average tap water pressure, percapita building area, and building age, suggesting pressure management in high-rise buildings is a key water-saving measure. Field tests of outflow characteristics under different water pressures indicated that over-pressure outflow (OPO) is a common cause of water wastage in buildings, however, no branch pipe pressure control measures were found in all the surveyed buildings. Laboratory tests showed that branch pipe pressure-reducing measures can lower water consumption and improve the comfortability of use as well. Therefore, in addition to applying high efficiency water-saving devices, we strongly recommend that branch pipe pressure-reducing measures should be strictly implemented in designing new building water supply systems and reconstruction of existing old building water supply systems, thereby, promoting water, energy saving and development of green building.展开更多
This study is concerned with the instability analysis and improvement of a high-pressure and highflow air pressure-reducing regulator(HPHFPRR).The outlet pressure of HPHFPRR abruptly exceeds the initial set pressure v...This study is concerned with the instability analysis and improvement of a high-pressure and highflow air pressure-reducing regulator(HPHFPRR).The outlet pressure of HPHFPRR abruptly exceeds the initial set pressure value under high-pressure and high-flow conditions.To address this instability issue of HPHFPRR during practical usage,this study conducted simulations to analyze the transient flow field characteristics under varying valve opening degrees,unlike most studies that focused on unsteady turbulent behaviors at fixed valve openings.The investigation examined variations in the internal flow field and air force acting on the valve spool at different degrees of valve opening for HPHFPRR.Moreover,a dynamic model was established to deeply analyze the motion process and forces experienced by the valve spool and piston in HPHFPRR,and an optimized spool structure was experimentally verified.Results demonstrated that the gas flow force acting on the valve spool was responsible for sudden outlet pressure rise in HPHFPRR.After design optimizations,the maximum gas flow force on the newly designed valve spool decreased by 32.7%during HPHFPRR opening,effectively resolving abnormal instability issues under high-pressure conditions encountered in projects.展开更多
In the ligh of the features of a superpressure system for hydrodynamic deep drawing (HDD) and the need of CNC, a pressure-reducer is applied. The dynamic performane’s stability of pressure-reducer,strength and sealin...In the ligh of the features of a superpressure system for hydrodynamic deep drawing (HDD) and the need of CNC, a pressure-reducer is applied. The dynamic performane’s stability of pressure-reducer,strength and sealing structure of cylinder are devised. The dynamic response of the pressure contro system is analyzed, based on which the sultable control pattern can be chosen.展开更多
A method named as 'volume-expanding and pressure-reducing adsorption' is proposed. It can be used to measure the isotherms under supercritical condition. The adsorption isotherms of phenol on activated carbons...A method named as 'volume-expanding and pressure-reducing adsorption' is proposed. It can be used to measure the isotherms under supercritical condition. The adsorption isotherms of phenol on activated carbons and polymeric adsorbents are estimated and compared respectively for the systems of 'phenol-activated carbon-supercritical fluid CO2' and 'phenol-polymeric adsorbent-supercritical fluid CO2'. The results show that the amount of phenol adsorbed on the activated carbons and the polymeric adsorbents under the supercritical condition is much less than that under the general condition, which can be utilized to develop a technology regenerating the activated carbon with supercritical fluid. Moreover, the effects of ethyl alcohol, used as the third component, on the isotherms of phenol on the activated carbons and polymeric adsorbents under the supercritical condition are also investigated.展开更多
文摘Facing the contradiction of water scarcity and water wastage in most cities of China, this study aims at probing into the factors influencing water-use efficiency and assessing water-saving potential by adopting pressure control measures based on field survey conducted in 23 high-rise buildings in Suqian, China and laboratory tests. Results showed that per capita water consumption (PCWC) exceeding water consumption norms is common in these buildings. The hourly water consumption variation law is quite different among different types of buildings. These differences should be considered in designing building water supply systems to lower water and energy consumption. On the basis of correlation analysis, the order of factors influencing the PCWC follows average tap water pressure, percapita building area, and building age, suggesting pressure management in high-rise buildings is a key water-saving measure. Field tests of outflow characteristics under different water pressures indicated that over-pressure outflow (OPO) is a common cause of water wastage in buildings, however, no branch pipe pressure control measures were found in all the surveyed buildings. Laboratory tests showed that branch pipe pressure-reducing measures can lower water consumption and improve the comfortability of use as well. Therefore, in addition to applying high efficiency water-saving devices, we strongly recommend that branch pipe pressure-reducing measures should be strictly implemented in designing new building water supply systems and reconstruction of existing old building water supply systems, thereby, promoting water, energy saving and development of green building.
基金supported by the National Natural Science Foundation of China(Grant No.51705164).
文摘This study is concerned with the instability analysis and improvement of a high-pressure and highflow air pressure-reducing regulator(HPHFPRR).The outlet pressure of HPHFPRR abruptly exceeds the initial set pressure value under high-pressure and high-flow conditions.To address this instability issue of HPHFPRR during practical usage,this study conducted simulations to analyze the transient flow field characteristics under varying valve opening degrees,unlike most studies that focused on unsteady turbulent behaviors at fixed valve openings.The investigation examined variations in the internal flow field and air force acting on the valve spool at different degrees of valve opening for HPHFPRR.Moreover,a dynamic model was established to deeply analyze the motion process and forces experienced by the valve spool and piston in HPHFPRR,and an optimized spool structure was experimentally verified.Results demonstrated that the gas flow force acting on the valve spool was responsible for sudden outlet pressure rise in HPHFPRR.After design optimizations,the maximum gas flow force on the newly designed valve spool decreased by 32.7%during HPHFPRR opening,effectively resolving abnormal instability issues under high-pressure conditions encountered in projects.
文摘In the ligh of the features of a superpressure system for hydrodynamic deep drawing (HDD) and the need of CNC, a pressure-reducer is applied. The dynamic performane’s stability of pressure-reducer,strength and sealing structure of cylinder are devised. The dynamic response of the pressure contro system is analyzed, based on which the sultable control pattern can be chosen.
基金Supported by the National Natural Science Foundation of China(No.29936100)and the National Science Foundation ofGuangdong Province(No.990629).
文摘A method named as 'volume-expanding and pressure-reducing adsorption' is proposed. It can be used to measure the isotherms under supercritical condition. The adsorption isotherms of phenol on activated carbons and polymeric adsorbents are estimated and compared respectively for the systems of 'phenol-activated carbon-supercritical fluid CO2' and 'phenol-polymeric adsorbent-supercritical fluid CO2'. The results show that the amount of phenol adsorbed on the activated carbons and the polymeric adsorbents under the supercritical condition is much less than that under the general condition, which can be utilized to develop a technology regenerating the activated carbon with supercritical fluid. Moreover, the effects of ethyl alcohol, used as the third component, on the isotherms of phenol on the activated carbons and polymeric adsorbents under the supercritical condition are also investigated.
