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Many researchers have performed experiments to investigate the structure and stability of different types of diffusion flames. A study was conducted to probe the mechanisms of diffusion flames situated behind two types of obstacles, namely, a backward facing step and a rectangular cylinder located upstream of a porous plate through which a fuel gas was injected. The results of the study are not meant to be used directly in the design of a practical burner or furnace but may provide insights on the mechanisms behind the stabilization of diffusion flames on different types of burners.

A microwave thermogravimetric analyzer was used to measure the characteristics of a mixture of palm oil solid waste (fiber, shell, and empty fruit bunch) and polyethylene terephthalate (PET). In the study, the range of palm oil solid waste composition ratios to PET used was 100:0, 75:25, 50:50, 25:75, and 0:100 (by weight). The study included the influence of the quality of raw material on the heating process. The mixture of palm oil solid waste (fiber, shell, and empty fruit bunch) and PET proved to impact the heating rate, mass-loss rate, and energy consumption. Based on the observation, empty fruit bunch-PET mixture had the highest heating rate (average 1.5039°C/s) than shell (average 0.6058°C/s), and fiber (0.9119°C/s) and also had the highest mass-loss rate (average 0.0253 g/s). The highest biomass (shell, empty fruit bunch, and fiber) and PET composition ratio give the highest rate of heating rate (average 1.8264°C/s) and mass-loss rate (average 0.02875 g/s). In addition, the increasing ratio of fixed carbon and material density will impact the increasing heating rate and mass-loss rate and decrease energy consumption. Therefore, fixed carbon and material gaps significantly affect the heating rate. [ABSTRACT FROM AUTHOR]

Torrefaction process is one of the solutions to produce solid fuel from a cocoa pod shell (CPS). Fuel characteristics of CPS changed after torrefaction. Effects of torrefaction temperature and holding time on physical, thermal, and chemical properties of CPS were investigated in this study. The experiments were conducted in a tubular torrefaction reactor. Three different torrefaction temperatures of 200, 250, and 300 °C and four holding times of 0, 30, 60, and 90 min were considered in this investigation. It was found that the color of CPS changed from light brown to black due to the increasing content of fixed carbon and depend on the torrefaction temperature and the holding time. The decrease in the grayscale value of the torrefied CPS represented an increase in HHV. Fixed carbon content and - higher heating value (HHV) of the torrefied CPS increased up to 17.5% and 41.3% compared to the raw CPS, while the volatile matter decreased up to 19.4%. The O/C and H/C atomic ratio decreased from 0.79 and 1.68 to 0.37 and 1.01, respectively, which corresponded to the increase of carbon content and decrease of oxygen and hydrogen contents. The properties of severe torrefaction CPS resembled between lignite and peat. The grindability and hydrophobicity of CPS was improved. The CPS based biochar should be used as a substitute for solid fuel that has the same characteristic to reduce the unfavorable effects of its potassium content. [ABSTRACT FROM AUTHOR]

Microwave technology has been extensively used as a heat source in co-pyrolysis processes. It provides several advantages such as fast and selective heating process, efficient use of energy, ability to increase quantity and quality of products, and controlling the development of hazardous produces and emissions so that it is considered environmentally-friendly. The use of biomass and polymers mixtures in microwave co-pyrolysis is expected to increase the number of products in the liquid phase because of the synergistic effect between gas products from biomass pyrolysis and hydrogen (as polymer pyrolysis products) which will encourage further formation of co-pyrolysis products. This review aims to increase the understanding of microwave used in the process of biomass and polymer co-pyrolysis. It also summarizes the direction of future researches to make the microwave energy more properly in the process of polymers and biomass mixture copyrolysis. The process optimization is to obtain liquid phase co-pyrolysis products especially biooil generated from pyrolysis that can be processed using the thermal cracking method in order to obtain bio-diesel products. [ABSTRACT FROM AUTHOR]

The choice for using a fighter fuselage in a fighter jet design affects a vortex generation advantageous in maneuverability. To study the effect of straight-body-type-fuselage (SBTF) on the vortex dynamic, a computational fluid dynamics (CFD) method is used, in order to simulate a model of SBTF fighter. The simulation uses Q-criterion to probe vortices, and a logarithmic grid to emphasize the micro-gridding effect of the turbulent boundary layer. The results show detailed quantitative velocity, pressure, trajectory of the vortex core, and wing negative surface pressure distribution (SPD), providing clear pictures of opportunity for performance improvement, better lift, agility, and maneuverability of a fighter if a model requires a new design. [ABSTRACT FROM AUTHOR]

Oil fields produce associated petroleum and wet gas, which can be mixed with commercial natural gas as fuel. Associated petroleum and wet gas are a low cost, low quality fuel, whereas commercial natural gas is the opposite. Two parameters are affected by this mixture: the fuel cost and the power – steam output of gas turbine – heat recovery steam generators. This research develops a Unit Commitment and Optimal Power Flow model based on Mixed Integer Nonlinear Programming to optimize combined heat and power cost by considering the optimal mixture between associated petroleum - wet gas and commercial natural gas. A thermodynamic model is used to represent the performance of gas turbine–heat recovery steam generators when subjected to different fuel mixtures. The results show that the proposed model can optimize cost by determining the most efficient power – steam dispatch and optimal fuel mixture. Furthermore, the optimization model can analyse the trade-off between power system losses, steam demand and associated - wet gas utilization. [ABSTRACT FROM AUTHOR]

The maneuverability of the Sukhoi Su-30 at very high angles of attack (AoA) was remarkably appealing. Canard angle, in cooperation with aircraft wing, created a flow pattern whereby, in that position, the fighter still had as much lifting force as possible in order not to stall. The behavior of changing canard angle configuration played an essential role in creating the strong vortex core so that it could delay the stall. The study of vortex dynamics at canard deflection angle gave an essential function in revealing the stall delay phenomenon. In this study, one could analyze the flow patterns and vortex dynamics ability of the Sukhoi Su-30-like model to delay stall due to the influence of canard deflection. The used of water tunnel facilities and computational fluid dynamics (CFD) based on Q-criterion has obtained clear and detailed visualization and aerodynamics data in revealing the phenomenon of vortex dynamics. It was found that between 30° and 40° canard deflection configurations, Sukhoi Su-30-like was able to produce the most robust flow interaction from the canard to the main wing. It was clearly seen that the vortex merging formation above the fighter heads was clearly visible capable of delaying stall until AoA 80°. [ABSTRACT FROM AUTHOR]