Jingzhou Zhang

Jingzhou Zhang
Nanjing University of Aeronautics and Astronautics · Department of Thermal Engineering

About

333
Publications
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3,699
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Publications

Publications (333)
Article
In this study, the thermal and hydraulic performances of horizontal grooved surfaces subjected to the piezo-fan ( PF) is numerically investigated. A total of four grooved surfaces with varying dimensionless edge length of the square groove cross-section ( EL = 0.25, 0.5, 0.75 and 1) and a corresponding baseline flat surface ( EL = 0) are considered...
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As the most classic method in fluid mechanics, pitot tubes have been widely employed to capture gauge pressure. Their effective operation is based on the premise that the measured fluid is ideal, irrotational, and incompressible, and the pitot tubes do not interfere with the measured flow field. However, in microscale Taylor–Couette flow with hyper...
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To pursue improvements in the power-to-weight ratio, cost-effectiveness ratio, and reliability in the energy industry, rotating machinery has been developed with higher rotational speeds and smaller sizes, resulting in complex aerodynamic behavior of the rotational shearing flow between rotator and stator. This study reports experimental measuremen...
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In industrial applications, Taylor–Couette–Poiseuille (TCP) flows are usually characterized by limited axial scope and eccentricity. The aerodynamic and thermal performance characteristics of these flows strongly depend on the coupling between the end leakage and axial throughflow. This study addressed the flow field and convective heat transfer ch...
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The implementation of heat sinks in high-power pulse electronic devices within hypersonic aircraft cabins has been facilitated by the emergence of innovative phase change materials (PCMs) characterized by excellent thermal conductivity and high latent heat. In this study, a representative material, layered porous media filled with paraffin wax, was...
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The integrated infrared suppressor can reduce the infrared radiation signal of a helicopter and is compatible with radar-acoustic stealth. However, the issues that are caused by the integrated infrared suppressor, such as temperature increases on the rear fuselage surface and a lack of shielding at the exhaust port, need to be addressed, in order t...
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Combined with infrared thermography measurements, large eddy simulation was used to study the square-wave pulsating film cooling on turbine vane at the time-averaged blowing ratios of 0.5 and 1.5. On suction surface, the introduction of coolant pulsation results in the decrease of cooling effectiveness. On pressure surface, coolant pulsation at hig...
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This paper proposes a new air cycle system by replacing the turbine assembly with vortex tubes and a parameter-matching method independent of the architecture of the air cycle system. Only, in terms of refrigerating and dehumidification, the performance of the newly proposed vortex system is worse than that of a conventional air cycle system under...
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Temperature-variation becomes increasingly evident when an impinging synthetic jet is restricted and confined excessively by the target plate. However, the confinement effect of the target plate on the temperature-variation effect during impinging heat transfer by a synthetic jet has not been clarified. In this study, impinging heat transfer by a s...
Article
Combined with infrared thermography tests, large eddy simulation was used to study the square-wave pulsating film cooling on flat plate at the time-averaged blowing ratios of 0.5 and 1.5. The effects of two pulsating parameters including frequency and amplitude were discussed in detail. At low blowing ratio, the introduction of coolant pulsation le...
Article
Therefore, this study employs Large Eddy Simulation to investigate the impinging heat transfer of the pulsed chevron jet on a semi-cylindrical concave plate at f=20Hz and H/d=4. The instantaneous temperature of the target plate is highly associated with the behavior of the pulsed jet. The temperature sharply decreases once it is covered by the cool...
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Two kinds of combined fluidic oscillators are designed by the structural innovation of the traditional fluidic oscillator. The working mechanism and flow characteristics of the combined fluidic oscillator are studied experimentally and numerically. The flow field characteristics of the combined fluidic oscillator are measured qualitatively and quan...
Article
In the recirculation zone behind the bluff-body, LES method was used to study the interaction mechanism of between the square-wave pulsating film cooling jet and recirculation vortexes. Combined with infrared thermography test results, having a detailed analysis at the time-averaged blowing ratios of 0.5 and 1.5. In model A, at low blowing ratio, t...
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The present work aims at numerically investigating on the flow and heat transfer performances induced by vibrating piezoelectric fan for cooling heated concave surfaces. Two main relevant parameters, relative curvature (K) of concave surface and moving-orientation of the piezoelectric fan, are taken into consideration. The relative curvature (K) is...
Article
Center cone locating at the rear portion of turbine is the key component of the integrated afterburner. Numerical studies were carried out to investigate full-coverage film cooling on center cone at engine-realistic conditions, and the effects of thermodynamic and geometric parameters on cooling effectiveness and aerodynamic loss were discussed in...
Article
In this paper, the thermal performance of the corrugated surfaces cooled with a piezoelectric fan was studied. A total of 25 corrugated surfaces with different wave shapes have been tested under different Re and gap heights ( G). The results showed that only the corrugated surface with the A/ W PF of 0.167 and T/ W PF of 0.533 produces the highest...
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This paper proposes an innovative bionic heat sink with micro barchan-dune-shaped humps for improving the flow and heat transfer performance of the smooth narrow channel. The effects of the Reynolds number of the main flow (Re) and pitch distance of the dune array (P) on the thermal-hydraulic performance are investigated. In this work, the air is t...
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The present study investigates the effects of upstream ramps on a backward-injection film cooling over a flat surface. Two ramp structures, referred to as a straight-wedge-shaped ramp (SWR) and sand-dune-shaped ramp (SDR), are considered under a series of blowing ratios ranging from M = 0.5 to M = 1.5. Regarding the backward injection, the key mech...
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Refrigeration using thermoelectric effect is a hot spot and frontier issue at present for its advantages of simple structure, no refrigerant, and no moving parts. This paper aims at characterizing the natural convection characteristics of air in the molding chamber of a 3-D printer that is cooled by thermoelectric cooling modules (TECMs). The distr...
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The axial throughflow cooling is a realistic solution for the purpose of thermal management in the hydrodynamic gas foil bearings operating at ultra-high rotational speed and mini bearing clearance. In order to illustrate the effects of axial throughflow cooling within the fluid-solid coupled heat transfer mode on the aerodynamic and thermal behavi...
Article
Large-eddy simulations were conducted to study the film cooling characteristics of a serrated trenched-hole cooling geometry on a scaled turbine guide vane. The simulations were carried out under a blowing ratio of M = 2.0. The serrated trench was placed on the suction and pressure side, respectively. The results show that the mainflow environment...
Article
A Plasma Synthetic Jet (PSJ) actuator is the promised equipment to produce a high-speed synthetic jet, which can be potentially applied to control the supersonic flow. Several researchers paid much attention to its application on Active Flow Control (AFC) in supersonic conditions, but the understanding of the flow field inner the cavity is extremel...
Article
Aerosol Infrared Stealth Technology is a novel method to suppress the infrared by releasing aerosol particles around the hot exhaust plume. However, the Infrared Radiation (IR) suppression rate is much lower in flight tests, which is caused by the unclear particle dispersion mechanism in high-speed non-isothermal shear flow. Hence, the large eddy s...
Article
The film cooling is a possible active thermal protection solution for the rotating detonation engines. As the rotating detonation wave is of high periodic and unsteady features, the film cooling characteristics inside the rotating detonation combustor are very complicated. To illustrate the influence of rotating detonation wave on the flow dynamics...
Article
A transient numerical simulation was carried out to investigate the convection heat transfer enhancement of heated asymmetrical concave surfaces using multi piezoelectric fans. And the numerical methodology has been validated through the comparison with the results of validation test. The effects of the relative curvature (RK), dimensionless fan-to...
Article
A sweeping jet generated by a unique class of fluidic device commonly known as fluidic oscillator is applied to the film cooling in this study. Unsteady Reynolds-averaged Navier–Stokes numerical simulations are conducted to reveal the film cooling mechanism of the sweeping jet. A comparative study of the sweeping jet and fan-shaped holes film is pe...
Article
A numerical investigation is performed to explore the thermal-fluid characteristics of corrugated surfaces with different wave shapes cooled by a vibrating piezoelectric fan. Totally nine different corrugated surfaces and one baseline flat surface are taken into consideration. Meanwhile, two non-dimensional parameters (A* and T*, representing the a...
Article
The integration of components is an important trend at present in the development of the afterburner. This study proposes a cooling structure of the guide plate to cope with the extreme thermal environment to which the flameholder is subjected. A numerical investigation is carried out to examine the effects of the cooling structure with different c...
Article
Rotor casing injection is one of the technical means for tip leakage flow control and casing thermal management. In the current investigation, a series of numerical simulations with the unsteady sliding mesh method are conducted to illustrate the effects of injection location, tip clearance, and shaped injection hole on the aerodynamic and cooling...
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Single-row double-jet film cooling (DJFC) of a turbine guide vane is numerically investigated in the present study, under a realistic aero-thermal condition. The double-jet units are positioned at specific locations, with 57% axial chord length (Cx) on the suction side or 28% Cx on the pressure side with respect to the leading edge of the guide van...
Article
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) h...
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Full-text available
Integrated design is a trend in the development of afterburners, and the distribution of cold flow is directly related to their flow field characteristics, combustion organization, and the cooling effect of components. Numerical simulations were performed to illustrate the effects of bypass flow distribution on the flow distribution, mixing charact...
Article
A numerical investigation is performed to study the serrated trenched-hole film cooling performance on the convex and the concave surfaces, with the use of a plenum coolant-fed mode. In current study, the relevant curvature of curved surface is varied as 2r1/d = 30, 60 and 90 at the convex side, 2r2/d = 90, 120 and 180 at the concave side. In addit...
Article
The heat transfer characteristics of a single synthetic jet (SJ) issuing from planar lobed orifice are investigated experimentally in current study. Two specific planar-lobed orifices (petal-shaped orifice and arch-shaped orifice) and two typical targets (flat target and semi-cylindrical concave target) are taken into consideration. For each lobed...
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Combing the advantages of film cooling, impingement cooling, and enhanced cooling by pin fins, laminated cooling is attracting more and more attention. This study investigates the effects of geometric and thermodynamic parameters on overall cooling effectiveness of laminated configuration, and model experiments were carried out to validate the nume...
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A type of supersonic fluidic oscillator is proposed and its ability to generate pulsating supersonic jet is proved in this paper. Unsteady two-dimensional numerical simulations reveal that the fluid transforms from subsonic to supersonic condition in the mixing chamber of oscillator after the supplied flow pressure increases from 1.1×10⁵ Pa to 5.0×...
Article
Numerical investigations are conducted to study the tip leakage flow and cooling effectiveness on various film-cooled squealer tips. The effect of partial squealer rims on the leakage flow structure, tip leakage loss and tip film-cooling effectiveness is illustrated under four blowing ratios by considering the relative motion between the turbine bl...
Article
The aerodynamic and cooling characteristics of the endwall were studied by numerical and experimental methods. Two film-hole configurations, i.e. conventional film-hole arrangement and partitioned film-hole arrangement, were taken into consideration. The partitioned film-hole arrangement is proposed based on the analysis of the heat load and the ne...
Article
The structural optimization of a specific laminated cooling structure is conducted under gas turbine combustor representative aero-thermal conditions, with the aim at improving its overall cooling effectiveness. The optimization procedure is realized by using conjugate heat transfer CFD analysis and radial basis function neural network (RBFNN) surr...
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This paper considers supersonic oscillators, in which the widths of the power nozzle and throat are the significant geometric parameters in characterizing the different internal flow characteristics. Supersonic fluidic oscillators with different power nozzle and throat widths are studied through time-dependent numerical computations. Two characteri...
Article
Combined with infrared thermography experiments, large-eddy simulation was used for studying trench film cooling on C3X vane model at the mainstream Reynolds number of 2.5 × 10⁵ based on the chord length, and nominal blowing ratios of 0.5 and 1.5. The instantaneous and time-averaged characteristics for trench film cooling were analzyed in detail. I...
Article
This paper describes a multi-objective optimization method for round-to-slot shaped film-holes (RTSH) using computational fluid dynamic analysis and surrogate model approximation. The physical model is a single-row of film cooling holes on a flat surface. Three design variables relating to the main RTSH geometric parameters are investigated: the fi...
Article
This study focuses on the temperature-variation effects in the piston-driven synthetic jet impingement and its influence on the definition of heat transfer coefficient. For this purpose, three test runs are conducted, including temperature variation test in the free synthetic jet, temperature variation test in the presence of an impinging target, a...
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A series of experimental tests are performed for the pulsating jet impingement heat transfer by varying the Reynolds number (5000 ≤ Re ≤ 15000), operation frequency (5 Hz ≤ f ≤ 40 Hz) and dimensionless nozzle-to-surface distance (2 ≤ H/d ≤ 10) while fixing the duty cycle as DC = 0.5. The maximum uncertainty in the measurement of Nusselt number is e...
Article
A tri-dimensional lobed nozzle is concerned in the jet impingement on a flat target and a concave target in the current study. The jet impingement heat transfer experiments are conducted under two jet Reynolds numbers (Re=10000 and 20000) and four nozzle-to-surface distances (H/d=2, 4, 6 and 8). Simultaneously, to characterize the flow dynamics of...
Article
Large eddy simulations were performed for film cooling on scaled-up C3X turbine vane at the nominal blowing ratio of M=0.5~1.5, and the Reynolds number, Re=3000, based on the mainstream inlet velocity and hole diameter. On the pressure surface, large-scale coherent structures including hairpin vortexes and horseshoe vortexes are generated in film-c...
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Full-text available
To address the curvature effect on single-row chevron-nozzle jet impingement heat transfer on concave surface, a series of experiments are conducted in the present investigation. Four concave surfaces including one semi-cylindrical concave surface and three parabolic concave surfaces with different width-to-depth ratios are tested under three typic...
Article
A numerical investigation is performed to study the effects of transverse trenches on the film cooling performances of single row film cooling holes on the turbine guide vane, under the engine-representative conditions. Two trenches are investigated in the current study, including a conventional straight trench and a novel serrated trench, both hav...
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Full-text available
A parametric design method, which was based on super-elliptical transition and self-adaption infrared radiation shield for the double S-shaped nozzle, was introduced. The complete shielding of high-temperature components in the S-shaped nozzle was realized. Model experiments and numerical simulations were performed to investigate the effects of off...