Subjects: Dynamic and Electric Engineering >> Engineering Thermophysics submitted time 2017-06-26 Cooperative journals: 《热科学学报》
Abstract：The advantage of high efficiency, low SFC (Specific Fuel Consumption), ultra-high bypass ratio turbofan engine attracts more and more attention in modern commercial engine. The intermediate turbine duct (ITD), which connects high pressure turbine (HPT) with low pressure turbine (LPT), has a critical impact on the overall performance of turbine by guiding flow coming from HPT to LPT without too much loss. Therefore, it becomes more and more urgent to master the technique of designing aggressive, even super-aggressive ITD. Much more concerns have been concentrated on the duct. However, in order to further improve turbine, LPT nozzle is arranged into ITD to shorten low pressure axle. With such design concept, it is obvious that LPT nozzle flow field is easily influenced by upstream duct structure, but receives much less interests on the contrary. In this paper, numerical method is used to investigate the effects of length of ITD with upstream swirl blades on LPT nozzle. Nine models with the same swirl and nozzle blades, while the length of ITD is the only parameter to be changed, will be discussed. Finally, several conclusions and advices for designers are summarized. After changing axial length of ducts, inlet and outlet flow field of nozzle differs, correspondingly. On the other hand, the shearing stress on nozzle blade (suction and pressure) surface presents individual feature under various inlet flow. In addition to that, "Clocking-like effect" is described in this paper, which will contribute much to the pressure loss and should be paid enough attention.
Subjects: Geosciences >> Space Physics submitted time 2017-03-10
Abstract： A novel single-layer microstrip reflectarray element with fractal structure is proposed. Ansoft HFSS is used to analyze the reflect phase for the fractal element in honeycomb lattice. A 469-element prime focus microstrip reflectarray antenna composed of the proposed fractal elements is designed, manufactured, and measured. The measured gain level of 29.8 dB is obtained at the center frequency of 13.58 GHz with 1-dB gain bandwidth of 15.3%. �2016 Wiley Periodicals, Inc.
Peer Review Status:
Awaiting Review
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