Humidification is an important step in humid air turbine system. The calculation on humidification is carried out at 423.15—573.15K, 5—15MPa. The results suggest that to produce high-enthalpy moist air, high water t...Humidification is an important step in humid air turbine system. The calculation on humidification is carried out at 423.15—573.15K, 5—15MPa. The results suggest that to produce high-enthalpy moist air, high water temperature and large water flow are needed. The water temperature is the most sensitive parameter to the humidification tower. And it is better for the humidification tower to work at temperature higher than 523 K when the system pressure is higher than 5 MPa. The comparison between the model used in this paper and ideal model shows that the ideal model can be used in simulation to simply the calculation when the temperature is lower than 473 K and pressure is lower than 5 MPa.展开更多
The trade-off between NO_(x)-soot and ISFC(Indicated Specific Fuel Consumption)brings new challenges for the development and application of innovative techniques that could reduce the NO_(x)-soot emissions of diesel e...The trade-off between NO_(x)-soot and ISFC(Indicated Specific Fuel Consumption)brings new challenges for the development and application of innovative techniques that could reduce the NO_(x)-soot emissions of diesel engine simultaneously with the lowest possible fuel penalty.In this study,the two coupling measures,advanced SOI(start of injection)respectively coupled with intake air humidification(IAH)and EGR,were used to achieve lower NO_(x)-soot emissions than the original engine while minimizing the increase in ISFC.Numerical studies were conducted on a four-stroke supercharged intercooled marine diesel engine under 75%loads at 1350 r/min by using AVL Fire code.The advanced SOI varied from 14.5°CA BTDC to 20°CA BTDC;humidity ratio ranged from 0 to 100%in increments of 20%,and EGR rate ranged from 0 to 25%in increments of 5%.The technical route to achieve Tier III emission standards was also analyzed in this paper.The result indicates that lower in-cylinder pressure,temperature and NO_(x)emissions,higher ISFC and soot emissions are observed when only IAH or EGR technology is applied,while opposite trends are found when only using advanced SOI.The proper combination of different SOI respectively with humidity ratio and EGR rate can improve the trade-off relationship between NO_(x)and soot.Meanwhile,the increase in ISFC is improved by using advanced SOI under high EGR rate or humidity ratio.Compared with the advanced SOI coupled with EGR,advanced SOI coupled with IAH results in less loss of ISFC.Analysis results reveal that both above-mentioned coupling measures can achieve low NO_(x)-soot emissions while ensuring that ISFC does not increase.As expected,there are nine combinations of advanced SOI coupled EGR that can achieve NO emissions to meet the Tier III standard,while advanced SOI coupled IAH has only one combination to meet this regulation.展开更多
The introduction of fresh air into the indoor space leads to a significant increase in cooling or heating loads.Solid desiccant heat pump fresh air unit which can handle the latent and sensible load of fresh air effic...The introduction of fresh air into the indoor space leads to a significant increase in cooling or heating loads.Solid desiccant heat pump fresh air unit which can handle the latent and sensible load of fresh air efficiently have been proposed recently.To improve the performance of the solid desiccant heat pump fresh air unit in the fresh air handling process,in this paper,the application of composite silica gel in a heat pump fresh air unit was investigated.The comparison between silica gel coating(SGC)and composite silica gel coating(CSGC)shows that the adsorption rate and water uptake capacity of CSGC are more than two times higher than those of SGC.An experimental setup for the solid desiccant heat pump fresh air unit was established.The performance of SGC and CSGC was tested in the setup successively.Results show that under summer conditions,compared with the solid desiccant heat pump fresh air unit using silica gel(SGFU),the average moisture removal and COP of the one using composite silica gel(CSGFU)increased by 15%and 30%,respectively.Under winter conditions,compared with SGFU,the average humidification and COP of CSGFU increased by 42%and 17%.With optimal operation conditions of 3 min switchover time and 40 r/s compressor frequency,the COP of CSGFU under summer conditions can reach 7.6.Results also show that the CSGFU and SGFU have higher COP and dehumidification rate under higher outdoor temperature and humidity ratio.展开更多
基金Supported by the Natural Science Foundation of Jiangsu Province (BK97124) the National Natural Science Foundation (No. 20376032)+1 种基金 the Outstanding Youth Fund of National Natural Science Foundation (No. 29925616)Key Fund of National Natural Science Fo
文摘Humidification is an important step in humid air turbine system. The calculation on humidification is carried out at 423.15—573.15K, 5—15MPa. The results suggest that to produce high-enthalpy moist air, high water temperature and large water flow are needed. The water temperature is the most sensitive parameter to the humidification tower. And it is better for the humidification tower to work at temperature higher than 523 K when the system pressure is higher than 5 MPa. The comparison between the model used in this paper and ideal model shows that the ideal model can be used in simulation to simply the calculation when the temperature is lower than 473 K and pressure is lower than 5 MPa.
基金financial support of the National Natural Science Foundation of China(Project 50676067)the National High Technology Research and Development Program of China(“863”Program)(Project 2012AA111705)。
文摘The trade-off between NO_(x)-soot and ISFC(Indicated Specific Fuel Consumption)brings new challenges for the development and application of innovative techniques that could reduce the NO_(x)-soot emissions of diesel engine simultaneously with the lowest possible fuel penalty.In this study,the two coupling measures,advanced SOI(start of injection)respectively coupled with intake air humidification(IAH)and EGR,were used to achieve lower NO_(x)-soot emissions than the original engine while minimizing the increase in ISFC.Numerical studies were conducted on a four-stroke supercharged intercooled marine diesel engine under 75%loads at 1350 r/min by using AVL Fire code.The advanced SOI varied from 14.5°CA BTDC to 20°CA BTDC;humidity ratio ranged from 0 to 100%in increments of 20%,and EGR rate ranged from 0 to 25%in increments of 5%.The technical route to achieve Tier III emission standards was also analyzed in this paper.The result indicates that lower in-cylinder pressure,temperature and NO_(x)emissions,higher ISFC and soot emissions are observed when only IAH or EGR technology is applied,while opposite trends are found when only using advanced SOI.The proper combination of different SOI respectively with humidity ratio and EGR rate can improve the trade-off relationship between NO_(x)and soot.Meanwhile,the increase in ISFC is improved by using advanced SOI under high EGR rate or humidity ratio.Compared with the advanced SOI coupled with EGR,advanced SOI coupled with IAH results in less loss of ISFC.Analysis results reveal that both above-mentioned coupling measures can achieve low NO_(x)-soot emissions while ensuring that ISFC does not increase.As expected,there are nine combinations of advanced SOI coupled EGR that can achieve NO emissions to meet the Tier III standard,while advanced SOI coupled IAH has only one combination to meet this regulation.
基金the financial support from the National Natural Science Foundation of China(No.51922070)supported by"the Fundamental Research Funds for the Central Universities"。
文摘The introduction of fresh air into the indoor space leads to a significant increase in cooling or heating loads.Solid desiccant heat pump fresh air unit which can handle the latent and sensible load of fresh air efficiently have been proposed recently.To improve the performance of the solid desiccant heat pump fresh air unit in the fresh air handling process,in this paper,the application of composite silica gel in a heat pump fresh air unit was investigated.The comparison between silica gel coating(SGC)and composite silica gel coating(CSGC)shows that the adsorption rate and water uptake capacity of CSGC are more than two times higher than those of SGC.An experimental setup for the solid desiccant heat pump fresh air unit was established.The performance of SGC and CSGC was tested in the setup successively.Results show that under summer conditions,compared with the solid desiccant heat pump fresh air unit using silica gel(SGFU),the average moisture removal and COP of the one using composite silica gel(CSGFU)increased by 15%and 30%,respectively.Under winter conditions,compared with SGFU,the average humidification and COP of CSGFU increased by 42%and 17%.With optimal operation conditions of 3 min switchover time and 40 r/s compressor frequency,the COP of CSGFU under summer conditions can reach 7.6.Results also show that the CSGFU and SGFU have higher COP and dehumidification rate under higher outdoor temperature and humidity ratio.
