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RISS 인기검색어
- 검색키워드
- 저자 : Zhihao Tang (검색결과 6 건)
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Tang, Zhihao,Liu, Peiqing,Guo, Hao,Yan, Jie,Li, Guangchao The Korean Society for Aeronautical and Space Scie 2015 International Journal of Aeronautical and Space Sc Vol.16 No.4
The numerical simulation of two-dimensional moving blade row interactions is conducted by CFD means to investigate the interactions between the front and rear propeller in a stratospheric airship contra-rotating open propeller configuration caused by different rotational speeds. The rotational speed is a main factor to affect the propeller Reynolds number which impact the aerodynamic performance of blade rows significantly. This effect works until the Reynolds number reaches a high enough value beyond which the coefficients become independent. Additionally, the interference on the blade row has been revealed by the investigation. The front blade row moves in the induced-velocity field generated by the rear blade row and the aerodynamic coefficients are influenced when the rear blade row has fast RPMs. The rear blade row moving behind the front one is affected directly by the wake and eddies generated by the front blade row. The aerodynamic coefficients reduce when the front blade row has slow RPMs while increase when the front blade row moves faster than itself. But overall, the interference on the front blade row due to the rear blade row is slight and the interference on the rear blade row due to the front blade row is much more significant.
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Performance of Contra-Rotating Propellers for Stratospheric Airships
Tang, Zhihao,Liu, Peiqing,Sun, Jingwei,Chen, Yaxi,Guo, Hao,Li, Guangchao The Korean Society for Aeronautical and Space Scie 2015 International Journal of Aeronautical and Space Sc Vol.16 No.4
Small advance ratio and low Reynolds number of stratospheric propulsion system bring lots of challenges to the design of propellers. Contra-rotating propeller configuration is proposed to improve the propulsion efficiency. In this paper, the feasibility of contra-rotating propeller for stratospheric airship has been assessed and its performance has been investigated by wind tunnel tests. The experimental results indicate, at relatively low Reynolds number, although the advance ratio is fixed, the performance of propellers is different with variation of Reynolds number. Moreover, at the same Reynolds number, the efficiency of contra-rotating propeller achieved appears to be a few percent greater than that for a standard conventional propulsion system. It can be concluded that contra-rotating propellers would be an efficient means to improve the performance of stratospheric airship propulsion system.
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Performance of Contra-Rotating Propellers for Stratospheric Airships
Zhihao Tang,Peiqing Liu,Jingwei Sun,Yaxi Chen,Hao Guo,Guangchao Li 한국항공우주학회 2015 International Journal of Aeronautical and Space Sc Vol.16 No.4
Small advance ratio and low Reynolds number of stratospheric propulsion system bring lots of challenges to the design of propellers. Contra-rotating propeller configuration is proposed to improve the propulsion efficiency. In this paper, the feasibility of contra-rotating propeller for stratospheric airship has been assessed and its performance has been investigated by wind tunnel tests. The experimental results indicate, at relatively low Reynolds number, although the advance ratio is fixed, the performance of propellers is different with variation of Reynolds number. Moreover, at the same Reynolds number, the efficiency of contra-rotating propeller achieved appears to be a few percent greater than that for a standard conventional propulsion system. It can be concluded that contra-rotating propellers would be an efficient means to improve the performance of stratospheric airship propulsion system.
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Zhihao Tang,Peiqing Liu,Hao Guo,Jie Yan,Guangchao Li 한국항공우주학회 2015 International Journal of Aeronautical and Space Sc Vol.16 No.4
The numerical simulation of two-dimensional moving blade row interactions is conducted by CFD means to investigate the interactions between the front and rear propeller in a stratospheric airship contra-rotating open propeller configuration caused by different rotational speeds. The rotational speed is a main factor to affect the propeller Reynolds number which impact the aerodynamic performance of blade rows significantly. This effect works until the Reynolds number reaches a high enough value beyond which the coefficients become independent. Additionally, the interference on the blade row has been revealed by the investigation. The front blade row moves in the induced-velocity field generated by the rear blade row and the aerodynamic coefficients are influenced when the rear blade row has fast RPMs. The rear blade row moving behind the front one is affected directly by the wake and eddies generated by the front blade row. The aerodynamic coefficients reduce when the front blade row has slow RPMs while increase when the front blade row moves faster than itself. But overall, the interference on the front blade row due to the rear blade row is slight and the interference on the rear blade row due to the front blade row is much more significant.
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Zhihao Si,Xin Zhang,Miao Zuo,Tao Wang,Yong Sun,Xing Tang,Xianhai Zeng,Lu Lin 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.2
2, 5-furandicarboxylic acid (FDCA) is a one of the most promising biomass-derived chemicals to substitute the non-renewable terephthalic acid as the monomer for producing polyethyleneterephthalate. At present, the oxidation of HMF is regarded as a prevalent way to prepare FDCA. Nevertheless, the isolation and storage of HMF is still a challenge. Herein, based on the higher stability of 5-formyloxymethylfurfural (FMF) than 5-hydroxymethylfurfural (HMF), we present an effective preparation route to prepare FDCA by substituting HMF with FMF as feedstock. A complete conversion of FMF and a 93.55% selectivity of FDCA were obtained in the mixed solvent of water and 1, 2- dioxane using Ru/C as catalyst and O2 as oxidant. An improved process was developed for preparing FDCA using FMF as feedstock. The investigation of conversion pathway showed that FMF and HMF were simultaneously oxidized to 2, 5-diformylfuran (DFF) in a case of the existence of the reversible equilibrium between FMF and HMF. Then DFF was oxidized to 5-formyl-2-furancarboxylic acid (FFCA). Subsequently, FFCA was oxidized to FDCA. In this process, the oxidation of FFCA to FDCA was determined as the rate-determining step. Furthermore, appropriate alkalinity favored the selectivity of FDCA and the conversion of FMF.
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Caixia Xiong,Yong Sun,Juan Du,Wei Chen,Zhihao Si,He Gao,Xing Tang,Xianhai Zeng 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.6
5-[(Formyloxy)methyl]furfural (FMF), an analogue of 5-(hydroxymethyl)furfural (HMF) is becoming more attractive due to its superior stability and hydrophobicity, which make it easier to refineand store. In the present study, FMF was produced from fructose by one-pot approach in pure formic acid media or by a two-step approach via HMF in choline chloride (ChCl)/fructose deep eutectic solvents (DES) system. A favorable FMF yield of 63.22% was reached by two-step approach. In addition, the effects of reaction parameters, such as temperature and acidity, on preparation of FMF from fructose were systematically investigated. The dehydration of fructose into HMF was confirmed as the rate-controlling step in the consecutive reaction. Ultimately, the separation and purification procedures of FMF were put forward. The FMF with a purity of 98.8% was obtained finally. Meanwhile, the FMF purified by saturated sodium bicarbonate solution showed an excelled storage stability.
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