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Tan L.,Nanjing University of Aeronautics and Astronautics | Zhang J.-Z.,Nanjing University of Aeronautics and Astronautics | Xu H.-S.,China Gas Turbine Establishment
International Journal of Thermal Sciences | Year: 2014

Convective heat transfer on the rib-roughened wall impinged by a row of air jets inside semi-confined channel was experimentally investigated. Four rows of transverse ribs were arranged in the wall-jet zone downstream from the impinging jet stagnation to enhance heat transfer. Three typical rib configurations, including orthogonal ribs, V-shaped ribs and inverted V-shaped ribs, were considered under different non-dimensional jet-to-target distances ranging from 1 to 3 diameters and impinging jet Reynolds numbers ranging from 6000 to 30,000. The results show that the rib-roughened wall enhances the convective heat transfer up to 30% in the ribbed region by comparison with the smooth wall under the same jet Reynolds number. Among three rib configurations, the inverted V-shaped rib seems to be advantageous on the convective heat transfer enhancement, especially at lower jet-to-target spacing. The ribs on the impinging target do provide stronger convective heat transfer in the wall-jet region, but at greater expense of pressure drop inside the channel. At the jet-to-target spacing ratio of 1, the flow coefficient of the rib-roughened channel is decreased 5%-10% in related to the smooth channel. © 2014 Elsevier Masson SAS. All rights reserved.


Wang J.,Shanghai JiaoTong University | Wang J.,China Gas Turbine Establishment | Wang L.W.,Shanghai JiaoTong University | Luo W.L.,Shanghai JiaoTong University | Wang R.Z.,Shanghai JiaoTong University
International Journal of Refrigeration | Year: 2013

A novel two-stage adsorption freezing machine, which is powered by the heat source with the temperature below 100°C was developed. The composite adsorbents of CaCl2 and BaCl2 developed by the matrix of expanded natural graphite were chosen as adsorbents. The performance of the system was tested, and the results showed that the system can generate the refrigerating power at -15°C for the coolant temperature of 25°C when the temperature of heat source is as low as 75°C. For the heat source of 85°C and the coolant temperature of 25°C, the optimal coefficient of performance (COP) and specific cooling power (SCP) at -15°C refrigeration are 0.127 and 100 W kg-1, respectively. COP and SCP increased with the increasing heat source temperature and decreased with the decreasing evaporating temperature; the influence of evaporating temperature is not as significant as that of the regeneration temperature. © 2012 Elsevier Ltd and IIR. All rights reserved.


Zhang C.,Beihang University | Lin Y.,Beihang University | Xu H.,China Gas Turbine Establishment | Xu Q.,Beihang University
Hangkong Xuebao/Acta Aeronautica et Astronautica Sinica | Year: 2014

In order to provide a development outlook of low emissions combustor technologies for civil aero-engine from the viewpoint of science and technology, the pollutant emissions controlling methods from rich burn and lean burn are expounded starting from the pollutant mechanism and basic principle, and the current development status of three kinds of low emissions combustion technologies is reviewed, including rich-quench-lean (RQL), lean premixed prevaporised (LPP), and lean direct injection (LDI). And the achieved level of new generation civil aviation low emissions combustor technologies is analyzed. The twin annular premixing swirler (TAPS) combustor using lean burn technology has been applied to aero-engine engineering with airworthiness certification, and it reduces NOx emissions by 50.0%-65.8% below CAEP/6 (Committee on Aviation Environmental Protection/6), reaching an ultra-low emissions level. It demonstrates the development potential of lean burn. To achieve the super ultra-low emissions goal of better than 75.0% NOx reduction relative to CAEP/6, it needs to conduct more in-depth research on spray, mixing, flow, combustion and their unsteady interactions, using advanced tools of combustion numerical computations and optical diagnostics.


Lin Y.,Beihang University | Li L.,Beihang University | Zhang C.,Beihang University | Xu H.,China Gas Turbine Establishment
Hangkong Xuebao/Acta Aeronautica et Astronautica Sinica | Year: 2014

Attention is now focused on the spray mixing characteristics of liquid jet injected into subsonic air crossflows as a development of low emission combustion technology. This paper summarizes the research progress in this field. The review is mainly about the experimental research work carried out at home and abroad, from three aspects: the atomization and breakup of a liquid jet in a crossflow, liquid jet penetration in the crossflow, and spray dispersion and transport in the crossflow. In most studies a liquid jet from a single plain orifice is transversely injected into a uniform airflow. The influences of fuel pulsation, shear layer and swirl in the airflow on spray mixing characteristics are studied experimentally. However, few studies are carried out on the mixing of an airblast-atomized liquid spray or multiple liquid jet injected into a crossflow. Finally a brief summary is given of the experimental studies on the spray mixing characteristics of a liquid jet injected into a crossflow. According to the review of the progress on the mixing characteristics of liquid jet, further research work is proposed by this paper with the application on atomization in advanced low emission combustors as the background.


Hu Y.,Harbin Institute of Technology | He Y.,Harbin Institute of Technology | Wang S.,Harbin Institute of Technology | Wang S.,China Gas Turbine Establishment | And 3 more authors.
Journal of Heat Transfer | Year: 2014

An experimental and numerical investigation on natural convection heat transfer of TiO2-water nanofluids in a square enclosure was carried out for the present work. TiO2-water nanofluids with different nanoparticle mass fractions were prepared for the experiment and physical properties of the nanofluids including thermal conductivity and viscosity were measured. Results show that both thermal conductivity and viscosity increase when increasing the mass fraction of TiO2 nanoparticles. In addition, the thermal conductivity of nanofluids increases, while the viscosity of nanofluids decreases with increasing the temperature. Nusselt numbers under different Rayleigh numbers were obtained from experimental data. Experimental results show that natural convection heat transfer of nanofluids is no better than water and even worse when the Rayleigh number is low. Numerical studies are carried out by a Lattice Boltzmann model (LBM) coupling the density and the temperature distribution functions to simulate the convection heat transfer in the enclosure. The experimental and numerical results are compared with each other finding a good match in this investigation, and the results indicate that natural convection heat transfer of TiO2-water nanofluids is more sensitive to viscosity than to thermal conductivity. © 2014 by ASME.


Li L.,University of Electronic Science and Technology of China | Shi W.,China Gas Turbine Establishment
Chinese Journal of Aeronautics | Year: 2015

Multi-sensor systems are very powerful in the complex environments. The cointegration theory and the vector error correction model, the statistic methods which widely applied in economic analysis, are utilized to create a fitting model for homogeneous sensors measurements. An algorithm is applied to implement the model for error correction, in which the signal of any sensor can be estimated from those of others. The model divides a signal series into two parts, the training part and the estimated part. By comparing the estimated part with the actual one, the proposed method can identify a sensor with possible faults and repair its signal. With a small amount of training data, the right parameters for the model in real time could be found by the algorithm. When applied in data analysis for aero engine testing, the model works well. Therefore, it is not only an effective method to detect any sensor failure or abnormality, but also a useful approach to correct possible errors. © 2015 The Authors.


Jun Z.,China Gas Turbine Establishment | Wei-Tao Z.,China Gas Turbine Establishment
22nd AIAA Computational Fluid Dynamics Conference | Year: 2015

A steady three-dimensional numerical calculation is performed in order to investigate the effect of rim sealing flow in a four-stage low pressure axial turbine. Mesh generation of the main flow domain and the sealing flow domain is performed with the structured multi-block grid. The finite volume flow solver ANSYS CFX 15.0 with SST k-ω turbulence model together with the transitional flow model is employed. The numerical approach is validated by comparing the results of calculations to measurement data on the design point. The flow field and secondary flow in the turbine with and without the sealing flow injection from rim seals are studied numerically. The results suggest that the sealing flow plays a major role in turbine performance and main structure of flow fields. It leads to a decreased turbine efficiency, to altered incidence angles and to an intensification of secondary flow structure. The rim seal leakage vortex generating at the rim seals interface enhances the passage vortex and results in the added flow loss. This proves that the effects of the sealing flow on turbine rotor performance are very large and should be considered in turbine design. In addition, an enhanced understanding of the interaction between the sealing flow and the main annulus flow are obtained. © 2015, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.


Yu Y.-Z.,Nanjing University of Aeronautics and Astronautics | Yu Y.-Z.,Nanjing Normal University | Zhang J.-Z.,Nanjing University of Aeronautics and Astronautics | Xu H.-S.,China Gas Turbine Establishment
International Journal of Heat and Mass Transfer | Year: 2014

Experimental study was conducted to investigate the heat transfer produced by single row of impinging jets inside a confined channel with different tab orientations of the triangular tabs at the jet exits. The effects of the tab number, tab orientation angle and tab penetration length on the jet impingement heat transfer behaviors were experimentally tested under nozzle-to-plate spacing of 1-3 diameters and jet Reynolds number of 10,000-20,000. A numerical computation was also carried out on the simulation of impinging jet flow fields to reveal the trends and differences observed in the heat transfer measurements. The results show that the presence of tabs increases the jet core velocity and induces array pairs of vortices, and hence enhances the heat transfer in the impingement region over the no-tab case. The tabs oriented upwards or downwards at 45 can better improve the heat transfer than the normal inclination case. The heat transfer enhancement produced by the tabs increases with the tab penetration length for the given range of 0.12-0.23 diameter. For the arrays of 4-12 triangular tabs, the array of 8 tabs seems to produce more effective heat transfer enhancement. © 2014 Elsevier Ltd. All rights reserved.


Yang D.-D.,China Gas Turbine Establishment
Hangkong Dongli Xuebao/Journal of Aerospace Power | Year: 2016

The principle of Fibonacci search method for performance optimization of aeroengine was introduced. The total performance model of turbojet containing two ejectors with variable area and Mach number was established. This aeroengine was optimized in maximum thrust mode, minimum fuel consumption mode and minimum turbine inlet temperature mode in the area of optimization parameters by using Fibonacci search method. The process of applying Fibonacci search method into the optimization was illustrated. The optimization results on different height and Mach number were given. Results show that, the constrained boundaries satisfied by the optimized performance are closely related with the flight height and Mach number. Different flight heights and Mach numbers correspond to different optimal control strategies. In spite of the flight mission, the targeted steady state performance from the control based on this optimization method is the best. This optimization method is not only applicable to the turbojet engine, but also lays a certain foundation for optimal control of other types of aeroengine. © 2016, Editorial Department of Journal of Aerospace Power. All right reserved.


Tong W.-J.,China Gas Turbine Establishment | Tang S.-J.,China Gas Turbine Establishment
Hangkong Dongli Xuebao/Journal of Aerospace Power | Year: 2011

On the basis of thermodynamics, gas dynamics and gas turbine principles, a detailed research on how to model the transient performance of a geared turbofan engine was performed, and the relevant solver equations were deduced simultaneously by employing constant mass flow (CMF) method in the paper. A geared turbofan engine transient model was successfully coded by means of employing the solver equations and C++ programming language. On the comparable basis, the calculation results have quite remarkable consistency with those results calculated by Gasturb 10, a famous commercial software in aero-engine performance simulation, with maximum errors within 1.5%. Hence, these consequences show the correctness and applicability of the solver equations.

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