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| 1 | Numerical Study of Effect of Compressor Swirling Flow on Combustor Design in a MTE显示文摘An effect of the swirling flow on the combustion performance is studied by the computational fluid dynamics(CFD) in a micro-gas turbine with a centrifugal compressor, dump diffuser and forward-flow combustor. The distributions of air mass and the Temperature Pattern Factor(as: Overall Temperature Distribution Factor-OTDF) in outlet are investigated with two different swirling angles of compressed air as 0° and 15° in three combustors. The results show that the influences of swirling flow on the air distribution and OTDF cannot be neglected. Compared with no-swirling flow, the air through outer liner is more, and the air through the inner liner is less, and the pressure loss is bigger under the swirling condition in the same combustor. The Temperature Pattern Factor changes under the different swirling conditions. | MU Yong WANG Chengdong LIU Cunxi LIU Fuqiang HU Chunyan XU Gang ZHU Junqiang | 2017 | Journal of Thermal Science2017，26，4： | 3 |
| 2 | Experimental Investigations of the Flow Field Structure and Interactions between Sectors of a Double-Swirl Low-Emission Combustor:Effects of Main Stage Swirl Intensity and Venturi Angle显示文摘Effect of venturi angle and main stage swirl intensity on flow field and interactions were investigated using PIV.The results showed the difference between the side sector and the middle sector was caused by interactions.The interactions were stronger with the rise of the main stage swirl intensity.When the swirl intensity was 0.7 and 0.9,there was little difference of the width of the recirculation zone.But the flow field had a great difference when the swirl intensity was 0.5 and 0.7,which means that when the swirl intensity was small,the swirl intensity had a great influence on the flow field.Venturi angle had a great influence on the flow field structure and interactions when the venturi angle was big,such as 90°.The venturi angle just had a small influence on the width of the recirculation zone when the venturi angle was relatively small,such as 28°and 52°.The velocity of the center plane between two sectors(plane 3)was small.There was a recirculation zone at upstream of the center plane between two sectors(plane 3)when the swirl intensity was 0.7 and 0.9,whereas not one when the swirl intensity was 0.5.The above was induced by interactions.In addition,the velocity of plane 1,plane 3,and plane 5 when the venturi angle was 52°was smaller than that of 28°and 90°. | FAN Xiongjie XU Gang LIU Cunxi ZHANG Chi WANG Jianchen LIN Yuzhen | 2020 | Journal of Thermal Science2020，29，3： | 3 |
| 3 | Numerical and experimental investigation on emission performance of a fuel staged combustor显示文摘The low NOx emission technology has become an important feature of advanced aviation engine.A wide range of applications attempt to take advantage of the fact that staged combustion under lean-premixed-prevaporized(LPP)conditions can significantly cut down emission and improve combustion efficiency.This paper proposes a scheme with fuel centrally staged and multi-point injection.The mixing of fuel and air is improved,and the flame temperature is relative low in combustion zone,minimizing the formation of nitrogen oxides(NOx),especially thermal NOx.In terms of the field distribution of equivalence ratio and temperature obtained from Computational Fluid Dynamics(CFD),a chemical reactor network(CRN),including several different ideal reactor,namely perfectly stirred reactor(PSR)and plug flow reactor(PFR),is constructed to simulate the combustion process and predict pollution emission.The influences of the pilot equivalence ratio and percentage of pilot/main fuel on NOx and carbon monoxide(CO)emission were investigated by CRN model.The effects of the pilot fuel and primary fuel on pollution emission were investigated experimentally.Finally,the effects of pilot equivalence ratio and pilot fuel proportion on NOx emission were discussed in detail by comparing predict of CRN and experimental results. | LIU FuQiang ZHANG KaiYu LIU CunXi MU Yong YANG JinHu XU Gang ZHU JunQiang | 2014 | Science China(Technological Sciences)2014，57，10： | 2 |
| 4 | Experimental Investigation on Ignition and Lean Blow-out Performance of a Multi-sector Centrally Staged Combustor显示文摘Improvement on extinction and pollution emission have become one of the most prominent research topics in gas turbine.It is widely recognized that the fuel/air mixture distribution in the recirculation zone is a critical factor in improving lean blow-out(LBO) and ignition.This paper proposed a new low emission scheme with fuel staged centrally and hybrid injector to improve flameout and emission.A relative small amount of fuel enters into central pilot airblast atomizer burner and then atomized by inner swirl air.The remaining majority of fuel is directly injected into vane channels of the primary swirler through a series of holes located on the sidewall of the main stage.Only pilot stage is fueled under ignition and lean flameout condition.The uniformity of fuel/air mixture distribution in the primary zone of the new design decreases NOX emission,meanwhile the fuel air mixture in pilot recirculation zone is locally rich to improve flameout and ignition.Experimental investigation was conducted to compare the new scheme with baseline design of dual-swirler in terms of LBO and ignition characteristics under the same condition in a multi-sector combustor.It is found that the fuel-air ratio of ignition limit and LBO decrease with the reference velocity increasing.The experimental results also show that the new scheme successfully improve lean blow-out and broaden the operation range of the combustor.The experimental results indicated that the centrally staged scheme can widen the operation boundary of the combustor and can provide guidance for design and optimization of combustion chamber. | LIU Fuqiang ZHANG Kaiyu MU Yong LIU Cunxi YANG Jinhu Xu Gang ZHU Junqiang | 2014 | Journal of Thermal Science2014，23，5： | 2 |
| 5 | Experimental Investigations of the Flow Field Structure and Interactions between Sectors of a Double-Swirl Low-Emission Combustor显示文摘In this paper,the flow field characteristics of a double-swirl low-emission combustor were analyzed by using Particle Imaging Velocimetry(PIV)technology in an optical three-sector combustor test rig.The interactions between sectors and the flow field structure were explained.The results illustrated that there was a big difference between the flow field structures of the middle sector and the side sector under the same pressure drop,which was mainly induced by the interactions between sectors.The interactions made the swirl intensity of the middle sector weaker than that of the side sector,which made the recirculation zone of the middle sector be smaller than that of the side sector.With the increase of swirler pressure drop,the jet velocity at the exit of the swirler,the jet expansion angle,the width of the recirculation zone and the recirculating speed of the central axis became larger,enhancing the interactions between air streams from middle sector and side sector.The flow velocity in the central plane between sectors was small,especially the radial velocity,mainly because of the loss of the swirl intensity by the interactions between flow field of adjacent sectors.The expansion angle determined the position of the vortex in the primary recirculation zone;the axial and radial position of the vortex move downstream and radial outward with the increase of the jet expansion angle.The results of the mechanism of flow field organization in this study can be used to support the design of new low-emission combustor. | FAN Xiongjie XU Gang LIU Cunxi WANG Jianchen LIN Yuzhen ZHANG Chi | 2020 | Journal of Thermal Science2020，29，1： | 2 |
| 6 | Experimental Studies on Fuel Spray Characteristics of Pressure-Swirl Atomizer and Air-Blast Atomizer显示文摘In this work,the effects of fuel temperatures and pressure drops on the flow field and spray characteristics of a pressure-swirl atomizer were discussed using the Particle Imaging Velocimetry(PIV),Planar Laser Induced Fluorescence(PLIF)and Laser Particle Size Analyzer(LPSA)methods.Then the air-blast atomizer was selected to study the interaction of initial atomization and flow field.The effect of fuel-air ratio on the air-blast atomizer were also considered,where the fuel-air ratio was varied by adjusting mass flow rate of the air and fuel respectively.The results show that the spray angle of the pressure-swirl atomizer increases first and changes a little after the pressure drop higher than 0.5 MPa.However,more fuel concentrate on the central region,which is mainly caused by the increase of the proportion of small droplets with lower centrifugal force.The fuel temperature can improve the spray angle only in lower pressure drop,and it has a little effect under higher pressure drops.In addition,the fuel pressure drop has an obvious influence on the fuel distribution and flow field near the nozzle exit compared with the downstream.For the air-blast atomizer,the spray angle increases compared with the pressure-swirl atomizer for the introduction of swirl air.Furthermore,the spray angle decreases with the air mass rate increasing,and it increases with the fuel mass rate increasing.The distribution of velocity and droplet near the nozzle exit is influenced by the air mass rate,and the fuel mass rate mainly affects the distribution in the downstream.The fuel accumulates in the annular area below the nozzle,and the distribution of it changes little with the development along the axial direction. | WANG Kaixing FAN Xiongjie LIU Fuqiang LIU Cunxi LU Haitao XU Gang | 2021 | Journal of Thermal Science2021，30，2： | 1 |
| 7 | Preparation of low-density superparamagnetic microspheres by coating glass microballoons with magnetite nanoparticles显示文摘 | Xiang Li Haibin Yang Wuyou Fu Cunxi Wu Shikai Liu Hongyang Zhu Xiaofen Pang | 2006 | Materials Science & Engineering B2006，，1： | 1 |
| 8 | Investigation of the Effect of Pilot Burner on Lean Blow Out Performance of A Staged Injector显示文摘The staged injector has exhibited great potential to achieve low emissions and is becoming the preferable choice of many civil airplanes. Moreover, it is promising to employ this injector design in military engine, which requires most of the combustion air enters the combustor through injector to reduce smoke emission. However, lean staged injector is prone to combustion instability and extinction in low load operation, so techniques for broadening its stable operation ranges are crucial for its application in real engine.In this work, the LBO performance of a staged injector is assessed and analyzed on a single sector test section.The experiment was done in atmospheric environment with optical access. Kerosene-PLIF technique was used to visualize the spray distribution and common camera was used to record the flame patterns. Emphasis is put on the influence of pilot burner on LBO performance. The fuel to air ratios at LBO of six injectors with different pilot swirler vane angle were evaluated and the obtained LBO data was converted into data at idle condition. Results show that the increase of pilot swirler vane angle could promote the air assisted atomization, which in turn improves the LBO performance slightly. Flame patterns typical in the process of LBO are analyzed and attempts are made to find out the main factors which govern the extinction process with the assistance of spray distribution and numerical flow field results. It can be learned that the flame patterns are mainly influenced by structure of the flow field just behind the pilot burner when the fuel mass flow rate is high; with the reduction of fuel, atomization quality become more and more important and is the main contributing factor of LBO. In the end of the paper,conclusions are drawn and suggestions are made for the optimization of the present staged injector. | YANG Jinhu ZHANG Kaiyu LIU Cunxi RUAN Changlong LIU Fuqiang XU Gang | 2014 | Journal of Thermal Science2014，23，6： | 1 |
| 9 | The Effect of Different Reaction Mechanisms on Combustion Simulation of a Reverse-Flow Combustor显示文摘Three different reaction mechanisms of kerosene and flamelet models were used to simulate combustion in a reverse-flow combustor.By comparing the effects of different mechanisms on the flow field characteristics,components and temperature distribution of the combustion chamber,the results showed that:Under different reaction mechanisms,there was a strong similarity between flow filed and temperature field,but the penetration depth and temperature distribution of local jets were affected by the mechanism.Due to the different reaction paths and reaction rates,the distribution of major components had a great degree of similarity,but the concentration of intermediate components varied greatly.Comprehensive analysis,the 16 species and 17 species reaction mechanisms can simulate the flow field and outlet temperature distribution of the combustor well. | LU Haitao LIU Fuqiang WANG Yulan FAN Xiongjie LIU Cunxi XU Gang | 2020 | Journal of Thermal Science2020，29，3： | 1 |
| 10 | Effects of all-trans retinoic acid on proliferation of human aorta smooth muscle cells显示文摘The primary cultured human aorta smooth muscle cells(SMCs)were characterized and theeffects of all—trans retinoic acid(atRA)on these cells were analysed.It is found that atRA could slowdown the growth rate of SMCs,and decrease the expression Ievels of cyclinDl,CDK4,c-myc at39%。38%and 43.6%respectively,while atRA had no effects on the expression of c^-actin which isspecific for SMCs.Results demonstrated that atRA inhibited cell growth of SMCs but did not induce celIdifferentiation.These effects may be clue to the decreased translation Ievels of cyclinDl.CDK4 andtranscription Ievel of c-myc.The fact that ati tA inhibited SMCs proIiferation may become one of thetheoretic basis for the cIinicaI use of atRA in the trea㈣t of SMCs proliferative diseases such asatherosclerosis. | Guoxia Liu Cunxi Li Lingfang Zeng Yongchao Wang | 1999 | Chinese Science Bulletin1999，44，5： | 0 |
| 11 | Tidal effects on intra-continental earthquake initiation in the Tibetan Plateau and its adjacent areas显示文摘To investigate the tidal effects on intra-continental earthquake initiation in the Tibetan Plateau and its surrounding areas,we selected over 1,500 focal mechanism solutions of inland earthquakes(epicenter locates at least 100 km to the coastlines)from Global Centroid Moment Tensor(GCMT)project and analyzed the values of tidal normal and shear stress as well as tidal Coulomb failure stress.For Coulomb failure stress calculation,we used Coulomb 3.40 software.We find that:(1)p-values of tidal stress change suggests a high tidal correlation of earthquake imitations with tidal normal stress change;(2)when tidal normal stress reached the local maximum values of compression and when tidal shear stress were closed to the positive peaks,earthquakes generated more frequently;(3)particular seismogenic environments such as strong continental plate interactions and the existence of fluids or rheologic substance possibly raise the tidal correlations and(4)higher sensitivity of earthquake initiation to earth tide presents along with higher seismicity,suggesting the rate of rain energy accumulation somehow has a dominating effect on the tidal correlation of earthquake initiation. | Guannan Liu Zhi Wang Cunxi Liu | 2020 | Earthquake Science2020，33，4： | 0 |
| 12 | Lean blowout characteristics of spray flame in a multi-swirl staged combustor under different fuel decreasing rates显示文摘Lean Blow Out(LBO)poses a significant safety hazard when occurring in aero-engines.Understanding the lower stability limits of gas turbine combustors and the characteristics of spray flame close to LBO are imperative for safe operation.The objective of this work is to evaluate the effects of fuel decreasing rates and pressure drops of the injector on LBO performances in a multiswirl staged combustor equipped with an airblast injector.A set of hardware and control system was developed to realize a user-defined fuel supply law.High-speed imaging was applied to record complete LBO processes under the conditions of linear fuel reduction and stable airflow.Partical Image Velocimetry(PIV)and Planar Mie(PMie)scattering were used to acquire the flow fields and spray fields under non-reacting conditions.Experimental results have shown that LBO limits extend to leaner conditions as the pressure drop of the injector increases.With an increase of the fuel decreasing rate,the exhaust temperature before flame extinction increases,and the LBO Fuel-to-Air-Ratio(FAR)decreases.The time evolution of the integral CH*intensity conforms to a linear function during the LBO process.Proper Orthogonal Decomposition(POD)was used to analyze the dynamic characteristics of lean-burn flames.Under different fuel decreasing rates and pressure drops of the injector,flames close to LBO present similar modal spatial distributions,alternately appearing axial,radial,high-order axial,and high-order radial oscillations. | Qianpeng ZHAO Jinhu YANG Cunxi LIU Fuqiang LIU Shaolin WANG Yong MU Gang XU Junqiang ZHU | 2022 | Chinese Journal of Aeronautics2022，35，12： | 0 |
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