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Improvement on shaped-hole film cooling effectiveness by integrating upstream sand-dune-shaped ramps

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Chinese Journal of Aeronautics 2021年第4期34卷 42-55页

作者： Shengchang zhang jingzhou zhang Xiaoming TAN College of Energy and Power Engineering Key Laboratory of Thermal Management and Energy Utilization of AircraftNanjing University of Aeronautics and AstronauticsNanjing 210016China

A numerical investigation and experimental validation is performed to address deeper insights into the combined effect of shaped holes and Sand-Dune-shaped upstream Ramp(SDR)on enhancing the film cooling effectiveness,under a wide blowing ratio range(M=0.25–1.5).Three kinds of holes(Cylindrical Hole(CH),Fan-Shaped Hole(FSH),and Crater-Shaped Hole(CSH))are taken into *** SDR shows an inherent affecting mechanism on the mutual interaction of *** aggravates the lateral spreading of cooling jet and thus improves the film cooling uniformity significantly,regardless of film-hole shape and blowing *** the blowing ratio is beyond 1.0,the combined effect of shaped holes and SDR on improving film cooling effectiveness behaves more *** is suggested that FSH-SDR is a most favorable film cooling *** FSH-SDR case,the spatially-averaged film cooling effectiveness is increased monotonously with the increase of blowing ratio,among the present bowing ratio range.

关键词： Adiabatic film cooling effectiveness Film cooling Numerical simulation Sand-dune-shaped ramp Shaped hole

Recent advances in film cooling enhancement:A review

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Chinese Journal of Aeronautics 2020年第4期33卷 1119-1136页

作者： jingzhou zhang Shengchang zhang Chunhua WANG Xiaoming TAN Jiangsu Province Key Laboratory of Aerospace Power System College of Energy and Power EngineeringNanjing University of Aeronautics and AstronauticsNanjing 210016China

Film cooling is an indispensable scheme in the design of highly-efficient cooling configurations to satisfy the thermal protection requirement of turbine hot section *** the last few decades,vast efforts have been paid on the discrete-hole film cooling *** this paper,some of the recent literatures related to the passive strategies(such as shaped film cooling holes,upstream ramps,shallow trenches,mesh-fed slots)and the active strategies(such as the use of pulsation modulating device or plasma actuator)for film cooling enhancement are surveyed,with the aim at presenting an updated overview about the state of the art in advanced film *** addition,some challenging issues are also outlined to motivate further investigations in such a broad topic.

关键词： Active strategy Cooling capacity Discrete-hole film cooling Film cooling enhancement Jet-in-crossflow Passive strategy

Investigation on film cooling characteristics from a row of converging slot-holes on flat plate

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Science China(Technological Sciences) 2011年第7期54卷 1793-1800页

作者： YAO Yu zhang jingzhou College of Energy and Power Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

Experimental and numerical researches were conducted to investigate the cooling performance of a single row of consoles （converging slot-hole） on a large-scale flat-plate model. The results show that the coolant flow from a row of consoles shows good lateral uniformity of adiabatic effectiveness, with regions of slightly enhanced cooling occurring between the consoles. For the console cooling geometry, the interaction between coolant jet from inclined console and the mainstream flow results in reasonable vortices configuration. A pair of counter rotating vortices originate from the edge of slot, not from the centerline of film holes and the rotating direction is contrary to conventional cylindrical hole. The heat transfer coefficient ratio is a tittle bigger for the console case than conventional cylindrical hole, and the discharge coefficient for a console is larger than that for cylindrical film cooling hole.

关键词： film cooling converging slot-hole cooling effectiveness heat transfer coefficient discharge coefficient

Control of squealer-tip leakage flow with perforated-rib coolant injection in an axial turbine cascade

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Chinese Journal of Aeronautics 2023年第8期36卷 54-73页

作者： Shengchang zhang Qinqin WANG Xiaoming TAN jingzhou zhang College of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China School of Energy and Power Engineering Beihang UniversityBeijing 100191China AECC Sichuan Gas Turbine Research Establishment Chengdu 610500China

A novel perforated-rib configuration is proposed for controlling the tip leakage flow at the rotor tip of an axial *** perforated-rib layouts are considered,wherein a perforated rib is installed at(A)the Suction-Side squealer(SS-rib),(B)the Pressure-Side squealer(PS-rib),and(C)the additional squealer along the blade Camber Line(CL-rib).A numerical method is used to show how the novel rib layouts affect the aerodynamic performance of the tip leakage *** show that the coolant jets issuing from the perforated-rib injection holes penetrate deeper into the tip clearance than those in the baseline squealer-tip case,and how the perforated-rib coolant injection affects the tip leakage flow depends strongly on the rib *** PS-rib and CL-rib layouts appear promising for controlling the tip leakage flow,playing a significant role in reducing the total pressure loss and improving the turbine blade’s isentropic *** particular,under an injection mass flow ratio of 1%and a tip clearance of 1%blade span,the PS-rib layout reduces the leakage mass flow rate by 27%and increases the isentropic efficiency by 1.25%compared with those in the baseline squealer-tip ***,the advantages of the PS-rib layout in tip leakage control are confirmed under small and large tip clearances.

关键词： Aerodynamics Perforatedrib Squealer tip Tip injection Tipleakageflow

Experimental study on flow and heat transfer characteristics of synthetic jet driven by piezoelectric actuator

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Science China(Technological Sciences) 2007年第2期50卷 221-229页

作者： zhang jingzhou TAN XiaoMing College of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

To investigate the flow and heat transfer characteristics of a synthetic jet driven by piezoelectric actuator, experimental investigation utilizing particle image veloci- metry, hot-wire anemometer and infrared camera was carried out. The results show that: (1) At the jet orifice exit, pairs of vortexes are generated, broken down and merged together periodically, forming a steady jet within a several slot width from distance near the orifice exit. And during the development, the synthetic jet spreads rapidly along the minor axis direction of the orifice. While along the major axis direction, the synthetic jet contracts firstly and then spreads slowly. (2) Exci- tation frequency forced on the actuator has a great effect on the synthetic jet flow field. There are two resonance frequencies at which the mean velocity and vorticity of the synthetic jet are maximized, especially at the higher resonance frequency. The resonance frequency values obtained by the experiment are lower than the theoretical values. (3) Similarly to the common jet impingement, the convective heat transfer coefficients at the target surface impinged by the synthetic jet also take on up-down tendency varying with the jet-to-surface spacing increment. But the jet-to-surface spacing ratio for optimum cooling achievement is greater and the cooling action region is wider than the former, indicating that the synthetic jet in- troduces a stronger entrainment and more vigorous penetration in the surrounding fluid.

关键词： synthetic jet impinging cooling flow heat transfer

Effects of forward-flight speed on plume flow and infrared radiation of IRS-integrating helicopter

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Chinese Journal of Aeronautics 2022年第3期35卷 155-168页

作者： Zongyao YANG jingzhou zhang Yong SHAN Key Laboratory of Thermal Management and Energy Utilization of Aircraft of Ministry of Industry and Information Technology College of Energy and Power EngineeringNanjing University of Aeronautics and AstronauticsNanjing 210016China

To address deeper understandings about the aero-thermal performance of an integrating infrared suppressor under more realistic situations,a numerical investigation is motivated in the current study,concerning the effects of forward-flight speed on exhaust plume flow and infrared radiation of the Infrared Suppressor-integrating(IRS-integrating)helicopter,wherein the forward-flight speed is changed from 0 m/s(hover state)to 100 m/s,while both the engine exhaust parameters and the main-rotor operation parameters remains unchanged during different forward-flight *** results show that the interaction between forward-flight flow and downwash flow alters the exhaust plume development and the internal flow inside the IRS-integrating rear fuselage more complicatedly,tightly dependent on the forward-flight *** particular concern is the situation where the forward-flight flow has nearly the same level as the downwash flow,the hot mixing flow could possibly interacts with the helicopter rear fuselage to play a local heating *** the increase of forward-flight speed,the ejection coefficient is generally increased and the average exhaust temperature of mixing flow is decreased,leading to a reduction of the infrared radiation intensity of exhaust plume in 3–5 lm ***,the influence of forward-flight speed on the overall infrared radiation intensity of IRS-integrating helicopter is conjectured not monotonous due to the complicated interaction between forward-flight flow and downwash *** high-speed forward-flight states,the overall infrared radiation intensity of the IRS-integrating helicopter in 3–5 lm band is reduced with the increase of forward-flight *** respect to 3–5 lm band,the forward-flight speed has little effect on the infrared radiation in 8–14 lm band.

关键词： Exhaust plume Forward-flight speed Helicopter Infrared radiation Integrating infrared suppressor

Thermo-elasto-hydrodynamic analysis of a specific multi-layer gas foil thrust bearing under thermal-fluid–solid coupling

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Chinese Journal of Aeronautics 2023年第12期36卷 231-246页

作者： Qihong GAO Wenjing SUN jingzhou zhang College of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Key Laboratory of Thermal Management and Energy Utilization of AircraftNanjing University of Aeronautics and AstronauticsNanjing 210016China

Gas foil bearing faces severe and complex thermal-fluid–solid coupling issues when in ultra-high speed and miniaturized impeller *** this study,a Thermo-Elasto-Hydrodynamic(TEHD)analysis of a specific multi-layer gas foil thrust bearing on the continuous loading process within a steady rotational speed is numerically investigated by a three-dimensional thermal-fluid–solid coupling *** indicate that the multi-layer foil exhibits nonlinear overall stiffness,with the thrust bottom foil serving as the primary elastic deformation structure,while the thrust top foil maintains a well-defined aerodynamic shape during a loading process,which helps reduce frictional damage and achieve an adequate loading *** low loads,the fluctuation of the gas film is extremely sensitive,and it weakens dramatically as the load *** viscous heating and friction torque exhibit a linear relationship with an increasing bearing load after a rapid *** on the exact stacking sequence and contact position of the multi-layer gas foil,the overlapping configuration allows for efficient transfer of viscous-shearing heat accumulated at the smallest air film through thermal conduction while providing elastic *** to the strong inhomogeneity of the viscous heat under varying loads,the temperature distribution on the top foil surface shows pronounced variations,while the difference between the peak and average temperatures of the thrust plate and top foil surfaces widens substantially with an increasing load.

关键词： Gas foil thrust bearing Thermo-elastohydrodynamic analysis Thermal-fluid–solid coupling simulation Adaptive deformation Structural stiffness

Optimization for aerodynamic performance of double serpentine nozzles with spanwise offsets using Taguchi-based CFD analysis

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Chinese Journal of Aeronautics 2023年第5期36卷 1-17页

作者： Xuyong zhang Yong SHAN jingzhou zhang Zhongcheng WU College of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Serpentine nozzles are widely used in combat aircraft to realize strong stealth *** on the layout characteristics within a confined space,a series of double serpentine nozzles with spanwise offsets are *** computational fluid dynamics and Taguchi method,the influence mechanisms of the Distribution of Area(DA),Distributions of Centerline for the first and second‘S’sections in the Vertical direction(DCV1 and DCV2),and Distribution of Centerline in the Spanwise direction(DCS)are *** impact of these factors on the total pressure recovery coefficient can be ranked as DA>DCV2>DCS>DCV1,whereas their impacts on the discharge coefficient and axial thrust coefficient can be ranked as DCV2>DCS>DA>*** the statistical significance of these factors,a nozzle in which DA changes rapidly at the exit and DCV1,DCV2,and DCS change rapidly at the entrance gives the best aerodynamic *** to the worst configuration,the total pressure recovery coefficient,discharge coefficient,and axial thrust coefficient are improved by 1.6%,3.5%and 3.6%,*** influences the gas flow acceleration in the entire serpentine channel,resulting in different wall shear stress and friction *** various centerline distributions influence the gas flow acceleration effects and form complex wave structures in the constantarea extension section,resulting in different local and friction losses.

关键词： Aerodynamics Analysis of Variance(ANOVA) Computational Fluid Dynamics(CFD) Double serpentine nozzle Spanwise offset Taguchi methods

Experimental study on heat transfer enhancement of square-array jet impingement by using an integrated synthetic jet actuator

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Science China(Technological Sciences) 2023年第12期66卷 3439-3449页

作者： TAN JunWen LYU YuanWei zhang jingzhou zhang JingYang College of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China College of Astronautics Nanjing University of Aeronautics and AstronauticsNanjing 210016China

A novel concept is proposed in the present study for improving the square-array jet impingement heat transfer by integrating a synthetic jet actuator into the array *** illustrate the potential of this concept,an experimental investigation is performed,wherein two jet Reynolds numbers(Re=3000 and 5000),three hole-to-hole pitches(X/d=Y/d=4,5 and 6),and three impinging distances(H/d=2,6 and 10)are considered while the synthetic jet is actuated at a fixed frequency of 180 Hz with a characteristic Reynolds number(Re_(0))of about *** results show that the synthetic jet has rare influence on the stagnation heat transfer of square-array jet but effectively improves the local heat transfer at the central zone of array *** potential is tightly dependent on the array layout,Reynolds number and impinging *** general,the spatially-averaged Nusselt number augment behaves more significantly for the situations with smaller jet Reynolds number and bigger impinging distance.

关键词： jet impingement heat transfer enhancement square-array jet synthetic jet actuator