Current Issue : January - March Volume : 2018 Issue Number : 1 Articles : 5 Articles
Although polymer-modified cement mortar (PCM) has been extensively used as finishing and repairing material, it is necessary\nto understand its combustion properties and mechanical properties at high temperature. This study evaluated the combustion\ncharacteristics with varying experimental parameters such as polymer type, unit polymer content, polymer-cement ratio, and\nthickness of the specimen. This study also evaluated the compressive strength and elastic modulus of PCMs with focus on the\neffects of the type of polymer, unit polymer content, and polymer-cement ratio. As a result, the incombustibility of the PCM was\nin the following order: SBR < VVA < EVA. After heating end, the mass loss rate of the PCM was less than 30%, regardless of the\npolymer type, unit polymer content, and W/C. In heat release rate test, the higher the unit polymer content, the greater the total heat\nrelease, regardless of the difference in W/C. The PAE series showed excellent fire resistance in the temperature range of 200âË?¼400âË?Ë?C.\nPCMs with a unit polymer content of 5%, modified with EVA and PAE, showed outstanding compressive strength at 200âË?¼400âË?Ë?C.\nAt elevated temperature, the modulus of elasticity of PCM declined with an increase in the unit polymer content, regardless of the\npolymer type....
The combination of emulsified diesel and low temperature combustion (LTC) technology\nhas great potential in reducing engine emissions. A visualization study on the spray and combustion\ncharacteristics of water emulsified diesel was conducted experimentally in a constant volume\nchamber under conventional and LTC conditions. The effects of ambient temperature on the\nevaporation, ignition and combustion characteristics of water emulsified diesel were studied under\ncold, evaporating and combustion conditions. Experimental results showed that the ambient\ntemperature had little effect on the spray structures, in terms of the liquid core length, the spray\nshape and the spray area. However, higher ambient temperature slightly reduced the Sauter Mean\nDiameter (SMD) of the spray droplets. The auto-ignition delay time increased significantly with\nthe decrease of the ambient temperature. The ignition process always occurred at the entrainment\nregion near the front periphery of the liquid core. This entrainment region was evolved from the early\ninjected fuel droplets which were heated and mixed by the continuous entrainment until the local\ntemperature and equivalence ratio reached the ignition condition. The maximum value of integrated\nnatural flame luminosity (INFL) reduced by 60% when the ambient temperature dropped from 1000\nto 800 K, indicating a significant decrease of the soot emissions could be achieved by LTC combustion\nmode than the conventional diesel engines....
Differences in the evolution of combustion in a single cylinder, DI (direct injection)\ndiesel engine fuelled by B20 were observed upon processing of the respective indicator diagrams.\nAiming to further investigate the effects of biodiesel on the engine injection and combustion process,\nthe injection characteristics of B0, B20, B40, B60, B80 and B100 were measured at low injection pressure\nand visualized at low and standard injection pressures. The fuel atomization characteristics were\ninvestigated in terms of mean droplet velocity, Sauter mean diameter, droplet velocity and diameter\ndistributions by using a spray visualization system and Laser Doppler Velocimetry. The jet break-up\ncharacteristics are mainly influenced by the Weber number, which is lower for biodiesel, mainly due\nto its higher surface tension. Thus, Sauter mean diameter (SMD) of sprays with biodiesel blended-fuel\nis higher. Volume mean diameter (VMD) and arithmetic mean diameter (AMD) values also increase\nwith blending ratio. Kinematic viscosity and surface tension become higher as the biodiesel blending\nratio increases. The SMD, VMD and AMD of diesel and biodiesel blended fuels decreased with\nan increase in the axial distance from spray tip. Comparison of estimated fuel burning rates for\n60,000 droplets� samples points to a decrease in mean fuel burning rate for B20 and higher blends....
CC Compliant Citation: This research intended to investigate combustion of liquid fuel in 3.5mm inner diameter quartz glass tube mesocombustor, based on liquid film evaporation by using heat recirculation.The mesocombustor has a copper section for heating and evaporating the liquid fuel. In mesocombustor type A, the fuel was glided through the narrow canal in the copper wall while the air was glided through the axial of combustor. The flame could only be successfully stabilized in high-ratio equivalent ranging from Ãâ?¢ = 1.1 to Ãâ?¢ = 1.6, due to the gap without combustion reaction caused by high air-fuel mixture over the limits of flame stability.Mesocombustor type B, which has annulus-shaped canal, could shift the flame stability from Ãâ?¢ = 0.8 to Ãâ?¢ = 1.2; however, it also narrowed the limits of flame stability due to the wall cooling. In mesocombustor type C, both liquid fuel and air were glided through the annulusshaped canal in the copper wall to fix the fuel evaporation and air mixture. The flame of type C was successfully stabilized, from Ãâ?¢ = 0.73 to Ãâ?¢ = 1.48 wider than types A and B. The flame of type C mesocombustor is circle-shaped and fitted to cross section of mesocombustor, but it still has thin gap without any flames due to thermal quenching by the wall....
The paper presents an analysis of the results of the both experimental results and theoretical works on the SI engine with additional expansion of exhaust gases, also known as five-stroke engine. The engine like this was constructed at Cracow University of Technology as a retrofitted in-line four cylinder engine in which outer cylinders (1st and 4th) work as fired cylinders and inner cylinders (2nd and 3rd) work as volume for the additional expansion. The aim of development of such an engine is to gain higher energy recovery ratio of the combusted fuel through the second expansion of exhaust in a separate cylinder. The operating parameters of the engine in various versions were analyzed: as naturally aspirated, supercharged using a turbocharger with a waste-gate valve and a turbocharger with variable nozzle turbine. Selected results of the indicating measurements of the engine with special emphasis on the indicated thermal efficiency were presented. The results pointed out the directions of further optimization of the engine. These results are all the more important, because according to the author�s knowledge, the research on the real object of this type are carried out in only one science center in the world besides Cracow University of Technology....
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