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A Comparative Review of the Experimental Mitigation Methods of the S-Shaped Diffusers in the Aeroengine Intakes 认领 引用
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作者 Hussain H.Al-Kayiem Safaa M.Ali +1 位作者 Sundus S.Al-Azawiey Raed A.Jessam 《Energy Engineering》 EI 2026年第2期68-103,共36页
Gas Turbines are among the most important energy systems for aviation and thermal-based power generation.The performance of gas turbine intakes with S-shaped diffusers is vulnerable to flow separation,reversal flow,an... Gas Turbines are among the most important energy systems for aviation and thermal-based power generation.The performance of gas turbine intakes with S-shaped diffusers is vulnerable to flow separation,reversal flow,and pressure distortion,mainly in aggressive S-shaped diffusers.Severalmethods,including vortex generators and energy promoters,have been proposed and investigated both experimentally and numerically.This paper compiles a review of experimental investigations that have been performed and reported to mitigate flow separation and restore system performance.The operational principles,classifications,design geometries,and performance parameters of Sshaped diffusers are presented to facilitate the analysis and understanding of the influence of each mitigation method on flowenhancement in S-shaped diffusers.Theinfluencing design parameters on the performance of the S-shaped diffuser and the findings achieved by various experimental investigations are discussed and compared.The review concludes that reducing the intake length reduces the size and weight of the gas turbine,leading to a higher power-to-weight ratio.However,the main challenge in shortening the S-shaped diffusers is the flow separation in the high-curvature section,which must be prevented to maintain high performance.Prevention can be achieved through flow control methods,which are categorized into passive and aggressive methods.The static pressure recovery coefficient,total pressure loss coefficient,ideal static pressure coefficient,distortion coefficient,and skin friction coefficient are the primary performance evaluation and comparison parameters between the experimentally investigated mitigation methods.The new trend in S-shaped diffuser studies includes the integration of computational and data-driven methods. 展开更多
关键词 Active flow control aeroengine air intake distortion coefficient gas turbine passive flow control pressure recovery S-shaped diffuser
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Performance analysis of diffuser-augmented wind turbines with swept rotor 认领 引用
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作者 Jean C.A.Nobre Silvia C.P.Andrade +3 位作者 David L.P.Sousa Tamara Guimarães Silvio B.Vale Jerson R.P.Vaz 《Global Energy Interconnection》 EI CSCD 2026年第2期405-418,共14页
This work presents a novel performance analysis model of diffuser-augmented wind turbines(DAWT)with swept blades,considering the influence of diffuser efficiency and thrust.Blade element momentum theory(BEMT)is extend... This work presents a novel performance analysis model of diffuser-augmented wind turbines(DAWT)with swept blades,considering the influence of diffuser efficiency and thrust.Blade element momentum theory(BEMT)is extended to incorporate the effect of blade sweep at each radial position along the rotor.An algorithm is developed and implemented to evaluate the performance of wind turbines with diffuser and sweep effect based on the BEMT model.The impact of the diffuser is assessed through the augmentation factor,defined as the ratio between the turbine efficiency and the Betz-Joukowsky limit.The comparison between the experiment and the algorithm considers the same rotor and diffuser geometry used by Hoopen[1].The straight blade is optimized to include the sweep effect.The model is validated using the experimental results provided by Hoopen[1],which include a power output of 531.0 W,a torque of 7.10 Nm,and a thrust coefficient of 0.80.The simulations using the proposed model with straight blades result in power of 532.6 W,torque of 7.10 Nm,and thrust coefficient of 0.77,compared to power of 531.0 W,torque of 7.10 Nm,and thrust coefficient of 0.80 from the experimental data.The optimized rotor with a forward sweep effect at 40°presented the highest power at 541.60 W,torque of 7.22 Nm,and a thrust coefficient of 0.63.Furthermore,the optimized rotor with backward sweep effect of 30°resulted in the highest power at 542.3 W,torque of 7.23 Nm,and a thrust coefficient of 0.69.The augmentation factor and power coefficient achieved a good gain in performance with the rotor optimized at 30°and 40°.Therefore,applying the sweep effect in a DAWT can result in a considerable increase in energy production. 展开更多
关键词 DAWT Swept blades BEMT model Diffuser
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Thermocline performance in a molten salt thermocline energy storage tank with annular-arranged and cross-arranged diffusers 认领 引用 被引量：1
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作者 Zheming TONG Haidan WANG +2 位作者 Shuiguang TONG Qi YANG Taotao NIE 《Journal of Zhejiang University-SCIENCE A》 SCIE EI CAS CSCD 2025年第4期339-358,共20页
The thermocline energy storage tank(TEST)serves as a crucial component in thermal energy storage systems,utilizing the working fluid that enters through a diffuser to store and harness energy.However,the conventional ... The thermocline energy storage tank(TEST)serves as a crucial component in thermal energy storage systems,utilizing the working fluid that enters through a diffuser to store and harness energy.However,the conventional double-plate radial diffuser is ill-suited for a single-medium TEST’s full tank storage due to its unidirectional fluid inflow.There has been a notable lack of optimization analysis of diffusers.Two innovative tubular diffuser designs with reduced cross-sectional areas have been introduced:the annular-arranged diffuser(AAD)and the cross-arranged diffuser(CAD).To elucidate the impact of diffuser designs on energy storage efficiency,a 3D transient computational fluid dynamics(CFD)model was established to simulate a thermocline formation under two diffuser types.The model was validated against experimental data.Results showed that the thermocline of AAD was 11.39%thinner than that of a traditional double-plate diffuser.In the process of charging and discharging,the time-varying thermocline and factors influencing thermocline thickness were analyzed.Results indicate that in the mixed dominant region,increased turbulent kinetic energy correlates with reduced thermocline thickness.Notably,the AAD’s stable thermocline was 4.23%and 5.41%thinner than the CAD’s during charging and discharging,respectively,making the AAD preferable for engineering applications.The effects of tube diameter and orifice opening angle on temperature stratification performance were also examined.The findings suggest that an inclined impact jet and large-diameter tubes are more conducive to temperature stratification.Moreover,an orifice diameter optimization method was developed,which can decrease the thermocline by 6.78%. 展开更多
关键词 Molten salt Thermocline Computational fluid dynamics(CFD) Diffuser Thermal energy storage
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Numerical Evaluation of the Performance Enhancement of S-Shaped Diffuser at the Intake of Gas Turbine by Energy Promoters 认领 引用 被引量：1
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作者 Hussain H.Al-Kayiem Raed A.Jessam +1 位作者 Sinan S.Hamdi Ali M.Tukkee 《Energy Engineering》 EI 2025年第4期1311-1335,共25页
Size reduction of the gas turbines(GT)by reducing the inlet S-shaped diffuser length increases the powerto-weight ratio.It improves the techno-economic features of the GT by lesser fuel consumption.However,this Length... Size reduction of the gas turbines(GT)by reducing the inlet S-shaped diffuser length increases the powerto-weight ratio.It improves the techno-economic features of the GT by lesser fuel consumption.However,this Length reduction of a bare S-shaped diffuser to an aggressive S-shaped diffuser would risk flow separation and performance reduction of the diffuser and the air intake of the GT.The objective of this research is to propose and assess fitted energy promoters(EPs)to enhance the S-shaped diffuser performance by controlling and modifying the flow in the high bending zone of the diffuser.After experimental assessment,the work has been extended to cover more cases by numerical investigations on bare,bare aggressive,and aggressive with energy promoters S-shaped diffusers.Three types of EPs,namely co-rotating low-profile,co-rotating streamline sheet,and trapezoidal submerged EPs were tested with various combinations over a range of Reynolds numbers from 40,000 to 75,000.The respective S-shaped diffusers were simulated by computational fluid dynamics(CFD)using ANSYS software adopting a steady,3D,standard k-εturbulence model to acquire the details of the flow structure,which cannot be visualized in the experiment.The diffuser performance has been evaluated by the performance indicators of static pressure recovery coefficient,total pressure loss coefficient,and distortion coefficient(DC(45°)).The enhancements in the static pressure recovery of the S-shaped aggressive diffuser with energy promoters are 19.5%,22.2%,and 24.5%with EPs at planes 3,4 and 5,respectively,compared to the aggressive bare diffuser.In addition,the installation of the EPs resulted in a DC(45°)reduction at the outlet plane of the diffuser of about 43%at Re=40,000.The enhancements in the performance parameters confirm that aggravating the internal flow eliminates the flow separation and enhances the GT intake efficiency. 展开更多
关键词 Energy promoters distortion coefficient gas turbine S-shaped diffuser static pressure recovery total pressure loss
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Mechanism of stall and surge in a centrifugal compressor with a variable vaned diffuser 认领 引用 被引量：21
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作者 Xiang XUE Tong WANG +1 位作者 Tongtong ZHANG Bo YANG 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2018年第6期1222-1231,共10页
To expand the stable operating range of compressors, understanding the mechanism of flow instability at low flow rates is necessary. In this paper, the mechanism of stall and surge in a centrifugal compressor with a v... To expand the stable operating range of compressors, understanding the mechanism of flow instability at low flow rates is necessary. In this paper, the mechanism of stall and surge in a centrifugal compressor with a variable vaned diffuser is experimentally investigated, where the diffuser blade setting angle can be adjusted. Many dynamic pressure transducers are mounted on the casing surface of the compressor. From the design condition to surge, dynamic pressure data is recorded throughout the gradual process. According to the signal developing status, the typical modes of compressor instability are defined in detail, such as stall, mild surge, and deep surge. A relatively high-frequency stall wave originates in the impeller and propagates to the diffuser, and finally stimulates a deep surge in the compressor. The compressor behavior during surge differs at different diffuser vane angles. When the diffuser vane angle is adjusted, both the unstable form and the core factor affecting the overall machine stability change. A specific indicator is proposed to measure the instability of each component in a compressor, which can be used to determine the best region for stability extension technologies, such as a holed casing treatment, in different compressor applications. 展开更多
关键词 Centrifugal compressor Flow instability Stall Surge Vaned diffuser
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Comparisons between numerical calculations and measurements in vaned diffuser of SHF impeller 认领 引用 被引量：6
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作者 Annie-Claude Bayeul-Lainé Patrick Dupont +4 位作者 Giovanna Cavazzini Patrick Cherdieu Antoine Dazin Gérard Bois Olivier Roussette 《排灌机械工程学报》 北大核心 2013年第12期1013-1020,共8页
The paper presents analysis of the performance and the internal flow behaviour in the vaned diffuser of a radial flow pump using PIV(particle image velocimetry)and pressure probe traverses.PIV measurements have alread... The paper presents analysis of the performance and the internal flow behaviour in the vaned diffuser of a radial flow pump using PIV(particle image velocimetry)and pressure probe traverses.PIV measurements have already been performed at middle height inside one diffuser channel passage for a given speed of rotation and various mass flow rates.These results have been already presented in several previous communications.New experiments have been performed using a three-hole pressure probe traverses from hub to shroud diffuser width at different radial locations between the two diffuser geometrical throats.Numerical simulations are also realized with the commercial codes Star CCM+7.02.011 and CFX.Frozen rotor and fully unsteady calculations of the whole pump have been performed.Comparisons between numerical results,previous experimental PIV results and new probe traverses one's are presented and discussed for one mass flow rate.In this respect,a first attempt to take into account fluid leakages between the rotating and fixed part of the pump has been checked since it may affects the real flow structure inside the diffuser. 展开更多
关键词 vaned diffuser radial flow pump unsteady flow numerical calculations particle image velocimetry(PIV) three-hole probe
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Numerical Study on Plume Interaction Above An AlternatingDiffuser in Stagnant Water 认领 引用 被引量：3
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作者 匡翠萍 李行伟 +1 位作者 刘曙光 顾杰 《China Ocean Engineering》 SCIE EI 2006年第2期289-302,共14页
The plume interaction above an alternating diffuser in stagnant water is studied with 3D Reynolds-averaged NavierStokes equations （RANS） combined with a buoyancy-extended κ-ε model. The steady three-dimensional tu... The plume interaction above an alternating diffuser in stagnant water is studied with 3D Reynolds-averaged NavierStokes equations （RANS） combined with a buoyancy-extended κ-ε model. The steady three-dimensional turbulent flow and temperature fields are computed by use of the finite volume method on a non-uniform high resolution orthogonal grid. The numerical predictions demonstrate a generic flow pattern for different turbulent heated jet discharges： the buoyant jets on each side of the diffuser first merge to form an essentially two-dimensional plume which bends back toward the diffuser centerline due to a low pressure cavity. In general, an under-pressure exists in the cavity until the plumes merge; the pressure increases to slightly positive afterwards. Two-dimensionality of the scalar and flow field is attained much later than the point of zero pressure. The position of merging point is governed by mainly four parameters - the discharge densimetfic Froude number, the port diameter and space, and the horizontal distance between alternating jet nozzles. A formula from numerical simulations is obtained through regression analysis and it is used to predict the position of plume merging point. The predicted temperature fields are comparable to previous experiments. 展开更多
关键词 alternating diffuser merging point plume interaction low pressure cavity ednsimetric Froude number turbulence modelling computational fluid dynamics κ-ε model enviromental hydraulics
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Investigation into the Interaction of Centrifugal Compressor Impeller and Vaneless Diffuser 认领 引用 被引量：3
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作者 杨策 张殿佐 +1 位作者 马朝臣 胡辽平 《Journal of Beijing Institute of Technology》 EI CAS 2006年第3期273-277,共5页
Centrifugal compressors with parallel-wall and contracting wall vaneless diffuser are designed by using centrifugal compressor computer-aided integrated design system. The internal flow fields of the compressor are ca... Centrifugal compressors with parallel-wall and contracting wall vaneless diffuser are designed by using centrifugal compressor computer-aided integrated design system. The internal flow fields of the compressor are calculated by solving three-dimensional Navier-Stokes equation. Four aspects are investigated and calculation results show that the total efficiencies and total pressure ratios of the compressor with contracting wall vandess diffuser is higher than that of the compressor with parallel-wall. The jet and wake don＇t mix rapidly inside vandess diffuser. The outlet blade lean angle doesn＇t affect the compressor performance. The greater the mass flow rate through impeller, the more uneven the velocity distribution at impeller outlet is. 展开更多
关键词 centrifugal compressor design three-dimensional viscous calculation jet-wake interaction of impeller and vaneless diffuser
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Numerical simulation investigations of energy-saving diffuser of main fan 认领 引用 被引量：5
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作者 CHEN Shi-qiang WANG Hai-qiao +1 位作者 CHENG Jian-lin LI Yi-qun 《Journal of Coal Science & Engineering(China)》 2010年第4期424-428,共5页
Based on the boundary condition of field engineering, numerical simulations of28 conditions of existing diffusers of 3 structure types were investigated by ComputationalFluid Dynamics software package, and there were ... Based on the boundary condition of field engineering, numerical simulations of28 conditions of existing diffusers of 3 structure types were investigated by ComputationalFluid Dynamics software package, and there were the problems of larger structure resistanceand lower diffusing efficiency of these diffusers by analysis of CFD results.Thestructure outlines of the energy-saving diffuser were constructed by the application ofstream function and potential function superimposing.On the basis of numerical simulationsof energy-saving diffusers of 5 area-enlarging ratios, structural resistances and diffusingefficiencies of 5 energy-saving diffusers were comparatively analyzed, and therange from 2.00 to 2.31 of the rational area-enlarging ratio of energy-saving diffusers wasderived.The optimization area-enlarging ratio of the energy-saving diffuser was presently2.28 through comparable analysis.From the above, the results show that the coefficient ofperformance of the energy-saving diffuser is better than 3 existing diffusers. 展开更多
关键词 main fan energy-saving diffuser optimization of outlines numerical simulation
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Real-time co-registered photoacoustic and ultrasonic imaging for early endometrial cancer detection driven by cylindrical diffuser 认领 引用 被引量：1
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作者 Yongping Lin Peter Andreae +2 位作者 Zhifang Li Jianyong Cai Hui Li 《Journal of Innovative Optical Health Sciences》 SCIE EI 2019年第2期1-12,共12页
In illuminating tissues,a cylindrical diffuser(CD)has an advantage over regular laser sources due to its ability to illuminate a larger volume of the target tissue.This paper presents a co-registered large volume phot... In illuminating tissues,a cylindrical diffuser(CD)has an advantage over regular laser sources due to its ability to illuminate a larger volume of the target tissue.This paper presents a co-registered large volume photoacoustic(PA)and ultrasonic(US)imaging for early endometrial cancer(EEC)detection using CD.It has the advantage that the US imaging system is outside the body and only the PA excitation device is inside the body,which makes the system more efficient and less invasive for EEC detection.The paper reports on two sets of experiments.Thefirst set produced real-time PA images of blood vessel phantom.The second set demonstrated the imaging of pig uterus ex vivo.The results show that the system has the potential for imaging and characterizing of EEC. 展开更多
关键词 Endometrial cancer cylindrical diffuser photoacoustic imaging
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Redesign of an 11 cm-diameter Micro Diffuser 认领 引用 被引量：2
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作者 陈杰 黄国平 《Chinese Journal of Aeronautics》 SCIE EI CAS 2010年第3期298-305,共8页
In order to improve the performances of an 11 cm-diameter turbine engine,this article suggests to substitute a new-style micro diffuser redesigned based on a new concept for the traditional diffuser having poor perfor... In order to improve the performances of an 11 cm-diameter turbine engine,this article suggests to substitute a new-style micro diffuser redesigned based on a new concept for the traditional diffuser having poor performances. The new diffuser comprises integral blades and splitters,which are taken for a series of ducts in designing. This article investigates the effects of the cross-section area distribution along the flow path on the redesigned diffuser＇s performances. Having furnished with the new diffuser in place of the original vaned one,the 11 cm-diameter prototype engine is tested on the rig for its performances. CFD and experiments have shown that the improved diffuser with the unchanged original size has gained excellent performance parameters of pressure coefficient over 0.65 and total pressure recovery coefficient over 0.9. Equipped with the redesigned micro diffuser,the engine increases the thrust by 11% and decreases the specific fuel consumption by 9%. 展开更多
关键词 aerospace propulsion new-style micro diffuser numerical analysis micro turbine engine centrifugal compressor
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Modeling of the Mixture of Wastewater Discharged from A Submerged Multiport Diffuser in Nantong Sea-Area 认领 引用 被引量：2
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作者 王超 王沛芳 《China Ocean Engineering》 SCIE EI 2005年第1期97-110,共14页
Laboratory experiments were conducted to investigate the mixture of wastewater discharged from a submerged multiport diffuser in the Nantong sea-area. The process was then simulated with a three-dimensional numerical ... Laboratory experiments were conducted to investigate the mixture of wastewater discharged from a submerged multiport diffuser in the Nantong sea-area. The process was then simulated with a three-dimensional numerical model. The plane or line patch was used to impose the discharge momentum flux in the near field. A comparison of model simulation with laboratory experiments shows that the proposed model can be used to simulate the shapes of pollution plumes, the distributions of excess concentration, and the velocity induced by a coflowing diffuser in proximity to a shoreline boundary. From the numerical simulation and laboratory experiments, it is recommended that the multiport diffuser be placed in a hydrodynamically active sea-area. 展开更多
关键词 wastewater discharge submerged multiport diffuser three-dimensional numerical model experiment
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Turbulence modelling of the aerodynamic interaction ofOGV wakes and diffuser flow 认领 引用 被引量：1
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作者 Page Gary McGuirk Jim 《航空动力学报》 EI CAS CSCD 北大核心 2011年第10期2302-2312,共11页
Different turbulence closures were used to predict the flow interaction between the wakes created by compressor outlet guide vanes(OGVs) and a downstream annular pre-diffuser.Two statistical turbulence models were tes... Different turbulence closures were used to predict the flow interaction between the wakes created by compressor outlet guide vanes(OGVs) and a downstream annular pre-diffuser.Two statistical turbulence models were tested based on the classical Reynolds-averaged Navier-Stokes(RANS) approach.Both high-Re and low-Re(Launder-Sharma) versions of the k-ε model were applied to a selected test problem for OGV wake/diffuser flows.The test problem was specifically chosen because experimentally determined inlet conditions and both profile and performance data were available to validate predictions.A preliminary study was also reported of the more advanced large eddy simulation(LES) approach.The LES sub-grid-scale(SGS) model was the basic Smagorinsky eddy viscosity assumption,with a Van-Driest damping function for improved capture of near-wall viscous behaviour.Comparison between the two RANS models showed little difference in terms of velocity contours at OGV trailing edge and diffuser exit.In terms of overall diffuser performance(static pressure recovery and total pressure loss coefficients),the high-Re model was shown to agree well with experimental data.The preliminary LES study indicates the highly unsteady character of the OGV wake flow,but requires improved treatment of inlet conditions. 展开更多
关键词 outlet guide vane(OGV) wakes diffuser flow interaction Reynolds-averaged Navier-Stokes(RANS) modelling large eddy simulation(LES) modelling
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Optimization Analysis of the Mixing Chamber and Diffuser of Ejector Based on Fano Flow Model 认领 引用
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作者 Lixing Zheng Weibo Wang +2 位作者 Yiyan Zhang Lingmei Wang Wei Lu 《Computer Modeling in Engineering & Sciences》 SCIE EI 2022年第10期153-170,共18页
An improved model to calculate the length of the mixing chamber of the ejector was proposed on the basis of the Fano flow model,and a method to optimize the structures of the mixing chamber and diffuser of the ejector... An improved model to calculate the length of the mixing chamber of the ejector was proposed on the basis of the Fano flow model,and a method to optimize the structures of the mixing chamber and diffuser of the ejector was put forward.The accuracy of the model was verified by comparing the theoretical results calculated using the model to experimental data reported in literature.Variations in the length of the mixing chamber Lm and length of the diffuser Ld with respect to variations in the outlet temperature of the ejector Tc,outlet pressure of the ejector pc,and the expansion ratio of the pressure of the primary flow to that of the secondary flow pg/pe were investigated.Moreover,variations in Lm and Ld with respect to variations in the ratio of the diameter of the throat of the motive nozzle to the diameter of the mixing chamber dg0/dc3 and ratio of the outlet diameter of the diffuser to the diameter of themixing chamber dc/dc3 were investigated.The distribution of flow fields in the ejector was simulated.Increasing Lm and dc3 reduced Tc and pc.Moreover,reducing pg/pe or dg0/dc3 reduced Tc and pc.The length of the mixed section Lm2,which was determined on the basis of the Fano flow model,increased as pg increased and decreased as dc3 increased.The mixing length Lm1,which was considered the primary flow expansion,showed the opposite trend with that of Lm2.Moreover,Ld increased as pg/pe and dc/dc3 increased.When the value of dc was 1.8 to 2.0 times as high as that of dc3,the semi-cone angle of the diffuser ranged between 6°and 12°.At a constant dc/dc3,decreasing Tc and pc increased Ld. 展开更多
关键词 Mixing chamber length Fano flow diffuser diameter ratio expansion ratio optimization method
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TURBULENT SEPARATED REATTACHED FLOW IN A TWO-DIMENSIONAL CURVED-WALL DIFFUSER 认领 引用
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作者 尹军飞 余少志 《Acta Mechanica Sinica》 SCIE EI CAS 1993年第2期117-123,共7页
A turbulent separation-rcattachment flow in a two-dimensional asymmetrical curved-wall diffuser is studied by a two-dimensional laser doppler velocimeter.The turbulent boundary layer separates on the lower curved wall... A turbulent separation-rcattachment flow in a two-dimensional asymmetrical curved-wall diffuser is studied by a two-dimensional laser doppler velocimeter.The turbulent boundary layer separates on the lower curved wall under strong pressure gradient and then reattaches on a parallel channel.At the inlet of the diffuser,Reynolds number based on the diffuser height is 1.2×10~5 and the velocity is 25.2m/s.The re- sults of experiments are presented and analyzed in new defined streamline-aligned coordinates.The experiment shows that after Transitory Detachment Reynolds shear stress is negative in the near-wall backflow region. Their characteristics are approximately the same as in simple turbulent shear layers near the maximum Reynolds shear stress.A scale is formed using the maximum Reynolds shear stresses.It is found that a Reynolds shear stress similarity exists from separation to reattachment and the Schofield-Perry velocity law ex- ists in the forward shear flow.Both profiles are used in the experimental work that leads to the design of a new eddy-viscosity model.The length scale is taken from that developed by Schofield and Perry.The composite velocity scale is formed by the maximum Reynolds shear stress and the Schofield Perry velocity scale as well as the edge velocity of the boundary layer.The results of these experiments are presented in this paper 展开更多
关键词 separating flow boundary layer turbulent flow turbulence model Laser Doppler Velocimeter two- dimensional diffuser
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EFFECT OF DUMP GAP ON TOTAL PRESSURE LOSS IN DUMP DIFFUSER 认领 引用
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作者 何小民 毛军逵 谈浩元 《Transactions of Nanjing University of Aeronautics and Astronautics》 2002年第2期157-160,共4页
The dump diffuser is an important component in advanced annular combustor, and its performance affects greatly the fluid field and pressure loss of the combustor. This paper presents the characteristics of the total p... The dump diffuser is an important component in advanced annular combustor, and its performance affects greatly the fluid field and pressure loss of the combustor. This paper presents the characteristics of the total pressure loss. Experiments and numerical simulations, keeping the inlet March number of prediffuser constant ( Ma =0 20), are carried out to obtain the regularity of the total pressure loss. It varies with the relative dump gap ( δ =1 2～3 0)by changing the position of prediffuser and combustor liner, respectively. Research shows that there exists the minimum total pressure loss ( σ *=1 6%～1 75%) when relative dump gap δ is about 1 8. 展开更多
关键词 dump diffuser relative dump gap pressure loss
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Optimal rotor blade swirl law for the last stage of a stationary turbine with an axial diffuser 认领 引用 被引量：1
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作者 Leonid Vokin Elena Semakina +4 位作者 Viktor Chernikov Viktor Rassokhin Viktor Barskov Aleksandr Sukhanov Mikhail Laptev 《Natural Gas Industry B》 2023年第5期436-444,共9页
Theflow kinetic-energy conversion into the pressure-forcesfield in the outlet turbine diffuser increases the heat drop to the last stage,generating additional power.The recovery properties of the diffuser are determin... Theflow kinetic-energy conversion into the pressure-forcesfield in the outlet turbine diffuser increases the heat drop to the last stage,generating additional power.The recovery properties of the diffuser are determined predominantly by the inlet boundary conditions of theflow formed by the last turbine stage.This study aims to demonstrate the influence of the last turbine stage swirl law on the boundary conditions formation at the diffuser inlet.The aerodynamics of the“turbine stageeexhaust diffuser”system(“SeD”system)was studied by an experi-mental method.The experimental results validated the numerical model of theflow in the“SeD”system.The stage's integral characteristics,the diffuser,and the“SeD”system were obtained for three system geometry variants.The results of the experiments revealed the indisputable advantage of the“negative”swirl law of the last turbine stage.An analysis of theflow structure based on the numerical simulation results revealed the details of the advantages of the boundary conditions at the diffuser inlet formed by the stage with a“negative”swirl compared with the stage with the traditional swirl law.Based on the results,recommendations for the“SeD”system design of powerful stationary gas turbines are proposed. 展开更多
关键词 Gas turbine Turbine stage Exhaust diffuser Blade apparatus swirl law Pressure restore coefficient Flow structure
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Receptivity and structural sensitivity study of the wide vaneless diffuser flow with adjoint method 认领 引用
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作者 Xiaocheng ZHU Chenxing HU +2 位作者 Zezhao LIU Hao LIU Zhaohui DU 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2018年第8期1679-1690,共12页
The stability of the flow in the vaneless diffuser of a centrifugal compressor is studied with the linear theory. The characteristics of direct and adjoint perturbation modes are investigated,and the receptivity of th... The stability of the flow in the vaneless diffuser of a centrifugal compressor is studied with the linear theory. The characteristics of direct and adjoint perturbation modes are investigated,and the receptivity of the instability mode to momentum forcing or mass injection is identified based on the adjoint modes. Analysis shows that the perturbation with the largest amplitude is located at the outlet of the vaneless diffuser, while the highest-receptivity region is located in the middle of the vaneless diffuser along the radial direction. The large difference between the direct and adjoint modes indicates that the instability mechanism cannot be identified from a study of either eigenmode separately. Therefore, the structural sensitivity analysis is adopted to study the feedback of the instability mode. The structural sensitivity of the eigenvalue which is proportional to the perturbation pressure and velocity is used to explain the mechanism of flow control for the vaneless diffuser. 展开更多
关键词 Adjoint method Receptivity Rotating stall Structural sensitivity Vaneless diffuser
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Concept of a swirling diffuser in batch blending tanks 认领 引用
19
作者 Wojciech Artichowicz Jerzy M.Sawicki 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2020年第2期378-382,共5页
The mixing of two or more components belongs to the category of the most common unit operations, both in technology and in nature. One particular version is homogenization(blending), the effectivity of which is strong... The mixing of two or more components belongs to the category of the most common unit operations, both in technology and in nature. One particular version is homogenization(blending), the effectivity of which is strongly related to the blending time. Among many differentiated individual solutions of mixing systems used in blenders, one should distinguish the class of agitators with diffusers. An analysis of the character of the velocity field during a blending chamber operation leads to the conclusion that it would be of avail to outfit a straight diffuser with different setups of elbows. In consequence, the vertical direction of the inflowing fluid stream would be changed into the horizontal direction of the outflowing stream, which should intensify the blending process. The concept has been verified experimentally, making use of the tracer methodology. The obtained results confirmed the theoretical conclusion that the blending time for the swirling-diffuser was shorter than for the classical straight one. 展开更多
关键词 Batch blending chamber Swirling diffuser Blending time
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ON THE THROUGHFLOW WITH SWIRLING INFLOW IN ANNULAR DIFFUSER 认领 引用
20
作者 俞纪伦 杨朝刚 王明德 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1992年第3期241-254,共14页
In this paper, a throughflow with swirling inflow in an annular diffuser is calculated. Under the assumption of small cross-flow, the flow near inner and outer wall surfaces is calculated based on the three-dimensiona... In this paper, a throughflow with swirling inflow in an annular diffuser is calculated. Under the assumption of small cross-flow, the flow near inner and outer wall surfaces is calculated based on the three-dimensional momentum integral equation of the boundary layer. The potential flow outside the boundary layer is computed by means of the iteration method based on the velocity gradient equation along the quasi-orthogonal direction of the meridional projection of the stream-line on the meridional surface and the constancy of flux equation[1]. The numerical results agree with the experiments quite well. This method is useful for analyzing the throughflow with pre-swirl in the annular diffuser. 展开更多
关键词 annular diffuser swirling inflow three-dimensional boundary layer small cross-flow
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