Thermal behaviour of blind-bolted connections to hollow and concrete-filled steel tubular columns

This paper reports on the thermal analysis of blind-bolts connected to concrete filled steel tube (CFST) and hollow steel section (HSS) columns. The aim is therefore the investigation of the temperature distribution in the connected sections and the evaluation of the effects due to concrete filling and anchored bolt extension. For this purpose, experimental and numerical work was carried out. The test programme involved twelve small- scale unloaded specimens where the variables were: tube section dimensions, type of blind-bolt, and hollow or concrete filled steel tubes. Results from the experiments revealed the noteworthy effect of concrete on bolt temperature reduction, the insignificant influence of tube section dimensions, and the limited impact of embedded bolt extension. Finite element models (FEM) of connections were developed to simulate the behaviour of tested pieces. Comparison with tests allowed the calibration of thermal material properties and characteristics of heat flux in interactions. Furthermore, assessments of heat transfer problem on the simulation of small-scale pieces extended to the numerical model of the whole endplate connection between an I-beam and a tubular column. Finally, the suitability of simple methods from Eurocode 3 Part 1.2 and other references to obtain the temperature on the connection was evaluated

Characterisation of high-pressure diesel-water emulsion sprays

Paper presented at the 7th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Turkey, 19-21 July, 2010.Combustion efficiency, emmissions and fuel economy in diesel engines are strongly dependent on the fuel spray characteristics such as spray penetration, atomization, droplet size distribution and cone angle. The quantitative information on the effect of fuel injection pressures on sprays characteristics is crucial for understanding the process of fuel mixture formation and the effects it may have on the combustion processes. This becomes even more important with the trend of using alternative fuels as a means of reducing emissions. This paper describes a study in a constant-volume vessel aimed at investigating the effect of injection pressure and water content in non-evaporating diesel-water emulsion sprays on droplet size and spray angle using Mie scattering and laser induced fluorescence measurement techniques.ej201

Performance of a DI diesel engine fuelled by blends of diesel and kiln-produced pyroligneous tar

This paper presents results of experiments undertaken to determine the performance of a direct injection (DI) diesel engine fuelled by blends of kiln-produced pyroligneous tar (PT) and diesel. The PT was sourced from Bulgaria where it was produced from a pine feedstock via a traditional kiln method that involves separation of the aqueous pyroligneous acid fraction. The tar is characterized by high carbon concentration, viscosity and high heating value. Although high, at fuel injection temperatures over 120 1C the tar’s viscosity is likelyto be lower than diesel. Analysis by GC revealed a number of compounds typically extracted from wood-based tar products. Blends containing 20% and 40% PT with diesel were tested in a 4-cylinder, 4-stoke DI diesel engine. The blends are stable and readily formed. Little difference in engine performance relative to diesel was found for 20% PT blends. PT blends (40%) exhibit significantly higher in-cylinder gas temperature and pressure. Ignition delay for both blends is longer than diesel, as is the fuel burn rate during the premixed stage of the combustion. During the diffusion stage of combustion, the fuel burn rate is lower relative to diesel. The performance of engines fuelled by blends containing 40% or more PTcould be improved through optimization of engine systems

Performance and Emission Assessment of Multi Cylinder Diesel Engine using Surfactant Enhanced Water in Diesel Emulsion

A four stroke, four cylinder, In-direct injection diesel engine was used to study the effect of emulsified diesel fuel with 5% water by volume on the engine performance and on the main pollutant emissions. The experiments were conducted in the speed range from 1000 to 4500 rpm at full load conditions. It was found that, in general, using emulsified fuel improves the engine performance with slight increase in emissions. While the BSFC has a minimum value for 5% water and at all rpm, the torque, the power and the BMEP are found to have maximum values under these conditions when compared conve ntional disel. CO2 was found to increase with engine speed whereas increase in CO and NOX were minimum. In this work water in diesel emulsion was prepared by a mechanical homogenizer and their physical and chemical properties were examined