Papers by Keyword: SMD

Abstract: This paper presents a verification of technology aspects for improvement of field effect capacity type gas sensor parameters by using laser micromilling technique for fabrication ceramic surface mounting device (SMD) package and microheater for sustentation working temperature of metal-insulator-semiconductor structure (MIS structure). Innovative claims include: demonstration of flexible opportunities for new digital fabrication process flows based on laser micromilling tech: fast design of SMD sensor 3-D model, flexible changing topology of microheater, thick and thin film technology combination for reducing of power consumption. The results show possibility to fast fabrication functional sensor in customer ceramic SMD package with base 9x9 mm with twice reduced power consumption and improving mechanical properties compare with classical metal-glass microelectronic packages using before for such type sensors.

Abstract: Fuel injection systems in modern diesel engines are designed and built to comply with very stringent environmental standards. They should also meet the highest level of fuel economy. Drivability, rapid response and easy and accurate control are a common demand. Changing the fuel characteristics could affect the performance of the fuel injection system. This study focuses on the evaluation of fuel spray characteristics of straight used cooking oil (SUCO) and its blends with petroleum diesel (PD) as a surrogate for pure PD. Used cooking oil blends have quite different physical properties from those of pure PD. Data for the lower heating value (LHV), density and viscosity were obtained from laboratory analysis. These data were merged with the physical and thermodynamic conditions of the diesel engine of interest to evaluate the dynamic behaviour of the fuel jet in 360° of crank rotation namely, the compression stroke, and the power stroke including the injection process. Engine operational conditions were calculated using a diesel dual thermodynamic cycle taking into account fuel injection adjustment at three different speeds, namely, idle speed, maximum torque speed and rated power speed. The results showed that fuel jet characteristics vary with SUCO content in the fuel blend. Two ranges of SUCO content in the blends were distinguished, 0 – 80% SUCO content and 80 – 100% SUCO content. Both showed a constant rate of change of jet characters per 10% increase in SUCO content in the fuel blend. Lower rates of change of fuel characters were observed at 0-80% SUCO content. The higher the temperature, the lower the rate of change of fuel jet characteristics.

Abstract: This paper shows the main steps to design and realize an original sound module for a miniature model steam locomotive, which produces the adequate sounds and the characteristic steam puffing in synchronization with the wheels of the locomotive. This continues the previous work of the authors concerning the model railroading and the implications of nonconventional technologies in this field of activity.

Abstract: The Sauter Mean Diameter (SMD) and spray cone angle are two important parameters that characterize spray performance. The objective of this study is to characterize palm olein/diesel blends spray in terms of spray angle and SMD under different injection pressures using a hollow cone pressure swirl atomizer. The physical properties of five diesel/palm olein blends, namely B5, B10, B15, B20 and B25 were measured and their spray characteristics were tested at injection pressures of 0.8MPa, 1.0MPa, and 1.2MPa under ambient atmospheric condition. The results were compared to spray established using petroleum diesel fuel. The SMD was measured using a phase Doppler analyzer (PDA). The spray cone angle was visualized using a digital single-lens reflex (DSLR) camera. The results indicated that petroleum diesel fuel had the widest cone angle followed by B5, B10, B15, B20 and B25 under the same injection pressure. Additionally, when the injection pressure increases from 0.8MPa to 1.2MPa, the spray cone angle widen accordingly. It is concluded that high content of palm olein in the palm biofuel blends increases viscosity and surface tension and hence higher value of SMD and narrower spray cone angle was generated. An increase in injection pressure resulted in smaller droplet SMD and wider spray cone angle.

Abstract: Injector is one of the vital devices in liquid rocket engine (LRE) as small changes in its configurations and design can result in significantly different LRE performance. Characteristics of spray such as spray cone angle, breakup length and Sauter mean diameter (SMD) are examples of crucial parameters that play the important role in the performance of liquid propellant rocket engine. Wider spray cone angle is beneficial for widespread of fuel in the combustion chamber for fast quiet ignition and a shorter breakup length provides shorter combustion chamber to be utilized and small SMD will result in fast and clean combustion. There are several mechanisms of liquid atomization such as swirling, e.g. jet swirl atomization or introducing bubbles into the liquid and effervescent atomization. Introducing a swirl component in the flow can enhance the propellant atomization and mixing whereas introducing bubbling gas directly into the liquid stream inside the injector leads to finer sprays even at lower injection pressures. This paper reviews the influence of both operating conditions and injector internal geometries towards the spray characteristics of swirl effervescent injectors. Operating conditions reviewed are injection pressure and gas-to-liquid ratio (GLR), while the injector internal geometries reviewed are limited to swirler geometry, mixing chamber diameter (d_c), mixing chamber length (l_c), aeration hole diameter (d_a), discharge orifice diameter (d_o) and discharge orifice length (l_o).

Abstract: The mathematical and physical model of the liquid propellant spray in straight nozzle was proposed for studying the performance characteristics of the small-scale liquid rocket engine. With the Fluent software, the numerical simulation was carried out. Sauter mean diameter (SMD) of the HAN-based liquid propellant (LP1846) in the engine combustor changing with spray pressure, nozzle diameter and the liquid surface tension were analyzed. The results indicate that: in the spray pressure region of 1.8MPa~3.0MPa, at a fixed spray pressure, the smaller is the nozzle diameter, the smaller is the droplets’ SMD and the relationship between the SMD and the nozzle diameter is approximately linearity; for the same nozzle diameter and spray pressure, the larger is the surface tension, the larger is the liquid droplets’ SMD.

Abstract: With the Phase Doppler Analyzer (PDA), the distribution characteristics of the liquid propellant simulated media produced by the designed counter dual-swirl air blast atomizer are studied. The results indicate that, the maximum axial mean velocity decreases with the increase of the axial distance away from the swirl exit plane, but the uniformity of the distribution along the radial direction are better and the differences among the degree axes decay. The circumferential distribution of the droplets’ diameter is uneven. The uniformity of the droplets’ diameter decreases after increases along with the radial direction. The mean diameters of the droplets increase first, and then decrease with the increase of the radial distance away from the center axis. The distribution of the droplets along the radial direction is better as the spray evolves to downstream.