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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. Source

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. Source

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. Source

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. Source

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. Source

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