On the turbulent flow models in modelling of omni-flow wind turbine

Yong Chen, Pei Ying, Yigeng Xu, Yuan Tian, 'On the turbulent flow models in modelling of omni-flow wind turbine', paper presented at The International Conference on Next Generation Wind Energy (ICNGWE2014), the Universidad Europa de Madrid, Madrid, Spain, 7th-10th October 2014.The computational fluid dynamics (CFD) has a wide application in the wind energy industry. In CFD simulations, a turbulence model plays a significantly important role in accuracy and resource cost. In this paper, a novel wind turbine, omni-flow wind turbine, was investigated with different turbulence models. Four turbulence models, standard k-ε, realizable k-ε, standard k-ω and SST k-ω models, were employed for this wind turbine in order to assess the best numerical configuration. The performance of these four turbulence models was validated with wind tunnel tests. It is evident that the realizable k-ε turbulence model is most suitable to simulate this novel wind turbine

An aerodynamic analysis of a novel small wind turbine based on impulse turbine principles

This document is the Accepted Manuscript of the following article: Pei Ying, Yong Kang Chen, and Yi Geng Xu, ‘An aerodynamic analysis of a novel small wind turbine based on impulse turbine principles’, Renewable Energy, Vol. 75: 37-43, March 2015, DOI: https://doi.org/10.1016/j.renene.2014.09.035, made available under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License CC BY NC-ND 4.0 http://creativecommons.org/licenses/by-nc-nd/4.0/The paper presents both a numerical and an experimental approach to study the air flow characteristics of a novel small wind turbine and to predict its performance. The turbine model was generated based on impulse turbine principles in order to be employed in an omni-flow wind energy system in urban areas. The results have shown that the maximum flow velocity behind the stator can be increased by 20% because of a nozzle cascade from the stator geometry. It was also observed that a wind turbine with a 0.3 m rotor diameter achieved the maximum power coefficient of 0.17 at the tip speed ratio of 0.6 under the wind velocity of 8.2 m/s. It was also found that the power coefficient was linked to the hub-to-tip ratio and reached its maximum value when the hub-to-tip ratio was 0.45. It is evident that this new wind turbine has the potential for low working noise and good starting feature compared with a conventional horizontal axis wind turbine.Peer reviewedFinal Accepted Versio

Numerical simulation of combined mixing and separating flow in channel filled with porous media

Various flow bifurcations are investigated for two dimensional combined mixing and separating geometry. These consist of two reversed channel flows interacting through a gap in the common separating wall filled with porous media of Newtonian fluids and other with unidirectional fluid flows. The Steady solutions are obtained through an unsteady finite element approach that employs a Taylor-Galerkin/pressure-correction scheme. The influence of increasing inertia on flow rates are all studied. Close agreement is attained with numerical data in the porous channels for Newtonian fluids.Peer reviewedSubmitted Versio

Aerospace vehicle

A dual structure aerospace vehicle is described which has an aeroshell structure and an internally disposed separable and reusable integral tank/thrust structure. The tank/thrust structure is inuslated for cryogenic fuels and the cavity within aeroshell is insulated from the tank/thrust structure. An internal support ring within the cavity serves as an attachment for lugs on the tank/thrust structure via double hinges. The aft end of tank/thrust structure is provided with rocket engines and exit nozzles with a trunnion supporting the tank/thrust structure within the aeroshell

NASA/DOD Aerospace Knowledge Diffusion Research Project. Paper 26: The relationship between technology policy and scientific and technical information within the US and Japanese aerospace industries

Government technology policy has nurtured the growth of the aerospace industry which is vital to both the U.S. and Japanese economies. Japanese technology policy differs significantly from U.S. technology policy, however, particularly with respect to the production, transfer, and use of scientific and technical information (STI). In this paper, we discuss the unique position of the aerospace industry in the U.S. and Japan, U.S. and Japanese aerospace policy, and the role of STI in the process of aerospace innovation. The information-seeking behaviors of U.S. and Japanese aerospace engineers and scientists are compared. The authors advocate the development of innovation-adoption technology and STI policy goals for U.S. aerospace and the inclusion of an aerospace knowledge diffusion transfer system with an 'active' component for scanning and acquiring foreign aerospace technology and STI

Strip yield modelling of fatigue crack under variable amplitude loading

The results from 'strip yield' approach of the FASTRAN type models of plasticity induced crack closure effects of fatigue cracks subjected to variable amplitude loadings are presented. The strip yield results are compared with authors' finite element (FE) and experimental results. It has been observed that the strip yield model is seen to be fundamentally limited by choice of alpha (constraint factor) and corresponding to treat baseline closure effects. Double overload closure behavior is functionally similar for both strip yield and FE models. Under multiple overloads, an important functional difference is seen between FE and strip yield models. This has been linked to the absence of in-plane constraint in the strip yield model, which is seen to have a distinct decreasing influence on on-going closure effects.Peer reviewedFinal Accepted Versio

Adhesives for Aerospace

The industry is hereby challenged to integrate adhesive technology with the total structure requirements in light of today's drive into automation/mechanization. The state of the art of adhesive technology is fairly well meeting the needs of the structural designers, the processing engineer, and the inspector, each on an individual basis. The total integration of these needs into the factory of the future is the next collective hurdle to be achieved. Improved processing parameters to fit the needs of automation/mechanization will necessitate some changes in the adhesive forms, formulations, and chemistries. Adhesives have, for the most part, kept up with the needs of the aerospace industry, normally leading the rest of the industry in developments. The wants of the aerospace industry still present a challenge to encompass all elements, achieving a totally integrated joined and sealed structural system. Better toughness with hot-wet strength improvements is desired. Lower cure temperatures, longer out times, and improved corrosion inhibition are desired

NASA/DOD Aerospace Knowledge Diffusion Research Project. Paper 14: An analysis of the technical communications practices reported by Israeli and US aerospace engineers and scientists

As part of Phase 4 of the NASA/DoD Aerospace Knowledge Diffusion Research Project, two pilot studies were conducted that investigated the technical communications practices of Israeli and U.S. aerospace engineers and scientists. Both studies had the same five objectives: first, to solicit the opinions of aerospace engineers and scientists regarding the importance of technical communications to their profession; second, to determine the use and production of technical communications by aerospace engineers and scientists; third, to seek their view about the appropriate content of an undergraduate course in technical communications; fourth, to determine aerospace engineers' and scientists' use of libraries, technical information centers, and on-line databases; and fifth, to determine the use and importance of computer and information technology to them. A self-administered questionnaire was mailed to randomly selected U.S. aerospace engineers and scientists who are working in cryogenics, adaptive walls, and magnetic suspension. A slightly modified version was sent to Israeli aerospace engineers and scientists working at Israel Aircraft Industries, LTD. Responses of the Israeli and U.S. aerospace engineers and scientists to selected questions are presented in this paper

[NASA/DOD Aerospace Knowledge Diffusion Research Project. Paper 7:] The NASA/DOD Aerospace Knowledge Diffusion Research Project: The DOD perspective

This project will provide descriptive and analytical data regarding the flow of STI at the individual, organizational, national, and international levels. It will examine both the channels used to communicate information and the social system of the aerospace knowledge diffusion process. Results of the project should provide useful information to R and D managers, information managers, and others concerned with improving access to and use of STI. Objectives include: (1) understanding the aerospace knowledge diffusion process at the individual, organizational, and national levels, placing particular emphasis on the diffusion of Federally funded aerospace STI; (2) understanding the international aerospace knowledge diffusion process at the individual and organizational levels, placing particular emphasis on the systems used to diffuse the results of Federally funded aerospace STI; (3) understanding the roles NASA/DoD technical report and aerospace librarians play in the transfer and use of knowledge derived from Federally funded aerospace R and D; (4) achieving recognition and acceptance within NASA, DoD and throughout the aerospace community that STI is a valuable strategic resource for innovation, problem solving, and productivity; and (5) providing results that can be used to optimize the effectiveness and efficiency of the Federal STI aerospace transfer system and exchange mechanism