In order to shorten aero-engine axial length,substituting the traditional long chord thick strut design accompanied with the traditional low pressure(LP) stage nozzle,LP turbine is integrated with intermediate turbine...In order to shorten aero-engine axial length,substituting the traditional long chord thick strut design accompanied with the traditional low pressure(LP) stage nozzle,LP turbine is integrated with intermediate turbine duct(ITD).In the current paper,five vanes of the first stage LP turbine nozzle is replaced with loaded struts for supporting the engine shaft,and providing oil pipes circumferentially which fulfilled the areo-engine structure requirement.However,their bulky geometric size represents a more effective obstacle to flow from high pressure(HP) turbine rotor.These five struts give obvious influence for not only the LP turbine nozzle but also the flowfield within the ITD,and hence cause higher loss.Numerical investigation has been undertaken to observe the influence of the Nozzle-Strut integrated design concept on the flowfield within the ITD and the nearby nozzle blades.According to the computational results,three main conclusions are finally obtained.Firstly,a noticeable low speed area is formed near the strut's leading edge,which is no doubt caused by the potential flow effects.Secondly,more severe radial migration of boundary layer flow adjacent to the strut's pressure side have been found near the nozzle's trailing edge.Such boundary layer migration is obvious,especially close to the shroud domain.Meanwhile,radial pressure gradient aggravates this phenomenon.Thirdly,velocity distribution along the strut's pressure side on nozzle's suction surface differs,which means loading variation of the nozzle.And it will no doubt cause nonuniform flowfield faced by the downstream rotor blade.展开更多
The meridian research situation and various meridian hypotheses of China in the past sixty years between 1950 and 2013 are summarized in the paper; possible existed problems in the process of current meridian research...The meridian research situation and various meridian hypotheses of China in the past sixty years between 1950 and 2013 are summarized in the paper; possible existed problems in the process of current meridian research are analyzed. Based on previous research results, we proposed that the essence of meridian can not be explained by the reductive analysis method, meridian research should be carried out under the guidance of overall concept of Chinese medicine theory. In this paper, combined with coherence theory of biophoton, we put forward the quantum interference hypothesis of meridian, which provides a possible research idea for meridian study.展开更多
Integrated observation platforms have been set up to investigate consequences of global change within a terrestrial network of observatories (TERENO) in Germany. The aim of TERENO is to foster the understanding of w...Integrated observation platforms have been set up to investigate consequences of global change within a terrestrial network of observatories (TERENO) in Germany. The aim of TERENO is to foster the understanding of water, energy, and matter fluxes in terrestrial systems, as well as their biological and physical drivers. Part of the Lower Rhine Valley-Eifel observatory of TERENO is located within the Eifel National Park. Recently, the National Park forest management started to promote the nat- ural regeneration of near-natural beech forest by removing a significant proportion of the spruce forest that was established for timber production after World War II. Within this context, the effects of such a disturbance on forest ecosystem functioning are currently investigated in a deforestation experiment in the Wtistebach catchment, which is one of the key experimental re- search sites within the Lower Rhine Valley-Eifel observatory. Here, we present the integrated observation system of the Wiistebach test site to exemplarily demonstrate the terrestrial observatory concept of TERENO that allows for a detailed mon- itoring of changes in hydrological and biogeochemical states and fluxes triggered by environmental disturbances. We present the observation platforms and the soil sampling campaign, as well as preliminary results including an analysis of data con- sistency. We specifically highlight the capability of integrated datasets to enable improved process understanding of the post-deforestation changes in ecosystem functioning.展开更多
基金supported by grants from the National Natural Science Foundation of China(No.51306177)
文摘In order to shorten aero-engine axial length,substituting the traditional long chord thick strut design accompanied with the traditional low pressure(LP) stage nozzle,LP turbine is integrated with intermediate turbine duct(ITD).In the current paper,five vanes of the first stage LP turbine nozzle is replaced with loaded struts for supporting the engine shaft,and providing oil pipes circumferentially which fulfilled the areo-engine structure requirement.However,their bulky geometric size represents a more effective obstacle to flow from high pressure(HP) turbine rotor.These five struts give obvious influence for not only the LP turbine nozzle but also the flowfield within the ITD,and hence cause higher loss.Numerical investigation has been undertaken to observe the influence of the Nozzle-Strut integrated design concept on the flowfield within the ITD and the nearby nozzle blades.According to the computational results,three main conclusions are finally obtained.Firstly,a noticeable low speed area is formed near the strut's leading edge,which is no doubt caused by the potential flow effects.Secondly,more severe radial migration of boundary layer flow adjacent to the strut's pressure side have been found near the nozzle's trailing edge.Such boundary layer migration is obvious,especially close to the shroud domain.Meanwhile,radial pressure gradient aggravates this phenomenon.Thirdly,velocity distribution along the strut's pressure side on nozzle's suction surface differs,which means loading variation of the nozzle.And it will no doubt cause nonuniform flowfield faced by the downstream rotor blade.
基金Supported by the Grant from National Natural Science Foundation of China(No.81273997 and 81173208)Ministry of Science and Technology of China(No.2014DFA30380)
文摘The meridian research situation and various meridian hypotheses of China in the past sixty years between 1950 and 2013 are summarized in the paper; possible existed problems in the process of current meridian research are analyzed. Based on previous research results, we proposed that the essence of meridian can not be explained by the reductive analysis method, meridian research should be carried out under the guidance of overall concept of Chinese medicine theory. In this paper, combined with coherence theory of biophoton, we put forward the quantum interference hypothesis of meridian, which provides a possible research idea for meridian study.
基金the support by the SFB-TR32 "Patterns in SoilVegetation-Atmosphere Systems:Monitoring,Modelling and Data Assimilation" funded by the Deutsche Forschungsgemeinschaft (DFG)TERENO (Terrestrial Environmental Observatories) funded by the Helmholtz Association of German Research Centers
文摘Integrated observation platforms have been set up to investigate consequences of global change within a terrestrial network of observatories (TERENO) in Germany. The aim of TERENO is to foster the understanding of water, energy, and matter fluxes in terrestrial systems, as well as their biological and physical drivers. Part of the Lower Rhine Valley-Eifel observatory of TERENO is located within the Eifel National Park. Recently, the National Park forest management started to promote the nat- ural regeneration of near-natural beech forest by removing a significant proportion of the spruce forest that was established for timber production after World War II. Within this context, the effects of such a disturbance on forest ecosystem functioning are currently investigated in a deforestation experiment in the Wtistebach catchment, which is one of the key experimental re- search sites within the Lower Rhine Valley-Eifel observatory. Here, we present the integrated observation system of the Wiistebach test site to exemplarily demonstrate the terrestrial observatory concept of TERENO that allows for a detailed mon- itoring of changes in hydrological and biogeochemical states and fluxes triggered by environmental disturbances. We present the observation platforms and the soil sampling campaign, as well as preliminary results including an analysis of data con- sistency. We specifically highlight the capability of integrated datasets to enable improved process understanding of the post-deforestation changes in ecosystem functioning.