Integration Of Strength and Process Modelling of Friction-Stir-Welded Fuselage Panels

In order to reduce potential uncertainties and conservatism in welded panel analysis procedures, understanding of the relationships between welding process parameters and static strength is required. The aim of this study is to determine and characterize the key process induced properties of advanced welding assembly methods on stiffened panel local buckling and collapse performance. To this end, an in-depth experimental and computational study of the static strength of a friction stir welded fuselage skin-stiffener panel subjected to compression loading has been undertaken. Four welding process effects, viz. the weld joint width, the width of the weld Heat Affected Zone, the strength of material within the weld Heat Affected Zone and the magnitude of welding induced residual stress, are investigated. A fractional factorial experiment design method (Taguchi) has been applied to identify the relative importance of each welding process effect and investigate effect interactions on both local skin buckling and crippling collapse performance. For the identified dominant welding process effects, parametric studies have been undertaken to identify critical welding process effect magnitudes and boundaries. The studies have shown that local skin buckling is principally influenced by the magnitude of welding induced residual stress and that the strength of material in the Heat Affected Zone and the magnitude of the welding induced residual stress have the greatest influence on crippling collapse behavior.


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3D Analysis of Heat Transfer Intensification by Re-Entrance Flow Pin-Fins Microstructures with a Highly Thermal-Conductive Plate

Joule heat-induced hot-spot formation sets severe limits in the operation of continuous annular electrochromatography (CAEC), a new concept for preparative separation as an analog to analytical capillary electrochromatography (CEC). This may lead to eluent flow perturbance, even to boiling, which would massively weaken separation efficiency and may even hamper the stationary phase used for separation. For reasons of system integration and high-efficiency heat transfer, micro flow heat exchangers are considered with a separate coolant flow. A 3D numerical analysis of the heat transfer of water single-phase laminar flow in a square microchannel and different arrays of micro pin-fins was carried out using COMSOL Multiphysics. Several advanced materials with low electric conductivity and at the same time with high heat conductivity were put forward to be used in the CAEC system. As essential design point, it is proposed to constitute the micro heat exchanger from two different parts of the CAEC system, namely a microstructured pin-fins plate and a so-called conductive plate.

Regional integration of biogas – developing an intersectoral research action plan for Northern Ireland

Bioenergy is a key component of the European Union long term energy strategy across all sectors, with a target contribution of up to 14% of the energy mix by 2020. It is estimated that there is the potential for 1TWh of primary energy from biogas per million persons in Europe, derived from agricultural by-products and waste. With an agricultural sector that accounts for 75% of land area and a large number of advanced engineering firms, Northern Ireland is a region with considerable potential for an integrated biogas industry. Northern Ireland is also heavily reliant on imported fossil fuels. Despite this, the industry is underdeveloped and there is a need for a collaborative approach from research, business and policy-makers across all sectors to optimise Northern Ireland’s abundant natural resources. ‘Developing Opportunities in Bio-Energy’ (i.e. Do Bioenergy) is a recently completed project that involved both academic and specialist industrial partners. The aim was to develop a biogas research action plan for 2020 to define priorities for intersectoral regional development, co-operation and knowledge transfer in the field of production and use of biogas. Consultations were held with regional stakeholders and working groups were established to compile supporting data, decide key objectives and implementation activities. Within the context of this study it was found that biogas from feedstocks including grass, agricultural slurry, household and industrial waste have the potential to contribute from 2.5% to 11% of Northern Ireland’s total energy consumption. The economics of on-farm production were assessed, along with potential markets and alternative uses for biogas in sectors such as transport, heat and electricity. Arising from this baseline data, a Do Bioenergy was developed. The plan sets out a strategic research agenda, and details priorities and targets for 2020. The challenge for Northern Ireland is how best to utilise the biogas – as electricity, heat or vehicle fuel and in what proportions. The research areas identified were: development of small scale solutions for biogas production and use; solutions for improved nutrient management; knowledge supporting and developing the integration of biogas into the rural economy; and future crops and bio-based products. The human resources and costs for the implementation were estimated as 80 person-years and £25 million respectively. It is also clear that the development of a robust bio-gas sector requires some reform of the regulatory regime, including a planning policy framework and a need to address social acceptance issues. The Action Plan was developed from a regional perspective but the results may be applicable to other regions in Europe and elsewhere. This paper presents the methodology, results and analysis, and discussion and key findings of the Do Bioenergy report for Northern Ireland.

Study on Hybrid Heat-Gas-Power Flow Algorithm for Integrated Community Energy System: 区域综合能源系统电/气/热混合潮流算法研究

With the integration of combined heat and power (CHP) units, air-conditioners and gas boilers, power, gas, and heat systems are becoming tightly linked to each other in the integrated community energy system (ICES). Interactions among the three systems are not well captured by traditional methods. To address this issue, a hybrid power-gas-heat flow calculation method was developed in this paper. In the proposed method, an energy hub model was presented to describe interactions among the three systems incorporating various CHP operating modes. In addition, three operating modes were proposed for the ICES including fully decoupled, partially coupled, and fully coupled. Numerical results indicated that the proposed algorithm can be used in the steady-state analysis of the ICES and reflect interactions among various energy systems.