Microfiltration is widely used in fine filtration operations, with dead-end filtration and cross-flow filtration. The microfiltration filter element or the microfiltration membrane is easy to be polluted by impurities...Microfiltration is widely used in fine filtration operations, with dead-end filtration and cross-flow filtration. The microfiltration filter element or the microfiltration membrane is easy to be polluted by impurities in the water and causes fouling, resulting in flux attenuation. The flux can be expressed by Darcy’s law and attenuation model. In this paper, two industrial titanium rod sintered filter elements (<span style="white-space:nowrap;"><span style="white-space:nowrap;">?</span></span>60 × 960 mm and <span style="white-space:nowrap;"><span style="white-space:nowrap;">?</span></span>60 × 960 mm) of different specifications are selected, and tap water (1.0 NTU) is used for constant pressure dead-end filtration. The amount tends to be the same, about 0.435 m<sup>3</sup><span style="white-space:nowrap;">·</span>m<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">?</span></span></span>2</sup><span style="white-space:nowrap;">·</span>h<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">?</span></span></span>1</sup>, which has nothing to do with the filtration accuracy of the filter element but only depends on the characteristics of the filter cake and the filter membrane. Through the analysis of the two models, it is found that the two filtration flux models are not universal and difficult to be applied in engineering.展开更多
Gasoline compression ignition(GCI)combustion faces problems such as high maximum pressure rise rate(MPRR)and combustion deterioration at high loads.This paper aims to improve the engine performance of the GCI mode by ...Gasoline compression ignition(GCI)combustion faces problems such as high maximum pressure rise rate(MPRR)and combustion deterioration at high loads.This paper aims to improve the engine performance of the GCI mode by regulating concentration stratification and promoting fuel-gas mixing by utilizing the double main-injection(DMI)strategy.Two direct injectors simultaneously injected gasoline with an octane number of 82.7 to investigate the energy ratio between the two main-injection and exhaust gas recirculation(EGR)on combustion and emissions.High-load experiments were conducted using the DMI strategy and compared with the single main-injection(SMI)strategy and conventional diesel combustion.The results indicate that the DMI strategy have a great potential to reduce the MPRR and improve the fuel economy of the GCI mode.At a 10 bar indicated mean effective pressure,increasing the main-injection-2 ratio(Rm-2)shortens the injection duration and increases the mean mixing time.Optimized Rm-2 could moderate the trade-off between the MPRR and the indicated specific fuel consumption with both reductions.An appropriate EGR should be adopted considering combustion and emissions.The DMI strategy achieves a highly efficient and stable combustion at high loads,with an indicated thermal efficiency(ITE)greater than 48%,CO and THC emissions at low levels,and MPRR within a reasonable range.Compared with the SMI strategy,the maximum improvement of the ITE is 1.5%,and the maximum reduction of MPRR is 1.5 bar/°CA.展开更多
文摘Microfiltration is widely used in fine filtration operations, with dead-end filtration and cross-flow filtration. The microfiltration filter element or the microfiltration membrane is easy to be polluted by impurities in the water and causes fouling, resulting in flux attenuation. The flux can be expressed by Darcy’s law and attenuation model. In this paper, two industrial titanium rod sintered filter elements (<span style="white-space:nowrap;"><span style="white-space:nowrap;">?</span></span>60 × 960 mm and <span style="white-space:nowrap;"><span style="white-space:nowrap;">?</span></span>60 × 960 mm) of different specifications are selected, and tap water (1.0 NTU) is used for constant pressure dead-end filtration. The amount tends to be the same, about 0.435 m<sup>3</sup><span style="white-space:nowrap;">·</span>m<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">?</span></span></span>2</sup><span style="white-space:nowrap;">·</span>h<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">?</span></span></span>1</sup>, which has nothing to do with the filtration accuracy of the filter element but only depends on the characteristics of the filter cake and the filter membrane. Through the analysis of the two models, it is found that the two filtration flux models are not universal and difficult to be applied in engineering.
基金supported by the National Key R&D Program of China(Grant No.2022YFE0100100).
文摘Gasoline compression ignition(GCI)combustion faces problems such as high maximum pressure rise rate(MPRR)and combustion deterioration at high loads.This paper aims to improve the engine performance of the GCI mode by regulating concentration stratification and promoting fuel-gas mixing by utilizing the double main-injection(DMI)strategy.Two direct injectors simultaneously injected gasoline with an octane number of 82.7 to investigate the energy ratio between the two main-injection and exhaust gas recirculation(EGR)on combustion and emissions.High-load experiments were conducted using the DMI strategy and compared with the single main-injection(SMI)strategy and conventional diesel combustion.The results indicate that the DMI strategy have a great potential to reduce the MPRR and improve the fuel economy of the GCI mode.At a 10 bar indicated mean effective pressure,increasing the main-injection-2 ratio(Rm-2)shortens the injection duration and increases the mean mixing time.Optimized Rm-2 could moderate the trade-off between the MPRR and the indicated specific fuel consumption with both reductions.An appropriate EGR should be adopted considering combustion and emissions.The DMI strategy achieves a highly efficient and stable combustion at high loads,with an indicated thermal efficiency(ITE)greater than 48%,CO and THC emissions at low levels,and MPRR within a reasonable range.Compared with the SMI strategy,the maximum improvement of the ITE is 1.5%,and the maximum reduction of MPRR is 1.5 bar/°CA.
