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EN
One of the main factors influencing on the optimal combustion process in a marine diesel engine’s cylinder is the fuel injection spray and the fuel atomization. The complexity of mentioned phenomena in the marine diesel engine’s cylinder may cause difficulties in their analysis. Measurement methods, allowing obtaining information about the process of fuel injection and evaporation in the diesel engine’s cylinder are qualified as optical visualization methods. It provides non-invasive measurement of parameters of fuel injection spray. The article presents the analysis of various aspects of optical measurement methods application that allow specifying parameters of fuel injection spray in the diesel engine’s cylinder. Initial studies were carried out using Mie scattering method. In addition, visualization obtained by shadowgraphy method was presented also. The constant volume chamber was used as a working area. The conventional light source was used in case of Mie scattering and a laser light source in shadowgraphy. For the lighting test was used a double-pulse Nd:YAG laser. The wavelength laser 532 nm was used. A course of the injection process was recorded by high-speed camera. The Mie scattering method allows analysing the fuel injection phenomena in macro scale. Specified geometric parameters. The shadowgraphy method allows to asses parameters of diesel fuel injection from marine diesel engine’s injector in the micro scale.
2
Content available Laser based diagnostic system for spray measurements
EN
The paper discusses the capabilities of the laser diagnostic system for dispersed multiphase flows measurements, which was recently commissioned at the Institute of Heat Engineering (ITC) at Warsaw University of Technology. The system presented in the paper is multifunctional and is capable to use different measurements techniques such as shadowgraphy, Mie scattering (scattering on the gas-liquid interface) and LIF (laser induced fluorescence). It provides possibility of switching from one technique to another depending on the characteristics of the observed combustion/injection mixing process. The operational features are discussed in-detail. The study presents the required and possible system setups. Special attention was focused on the system components, which are needed for relevant measurement techniques. Moreover, the limitations of the measurement techniques are discussed and the example measurements are presented. The study shows that using different techniques extends the measurement capabilities of the system with minimum investment costs. This results from the fact that certain system components for different techniques are the same. Moreover, one can conclude that the system design allows certain measurement methods to be applied simultaneously, which results in synergy by making possible drawing more advanced conclusions on observed phenomena
3
Content available remote Estimation of Apollo Lunar Dust Transport using Optical Extinction Measurements
EN
A technique to estimate mass erosion rate of surface soil during landing of the Apollo Lunar Module (LM) and total mass ejected due to the rocket plume interaction is proposed and tested. The erosion rate is proportional to the product of the second moment of the lofted particle size distribution N(D), and third moment of the normalized soil size distribution S(D), divided by the integral of S(D)⋅D2/v(D), where D is particle diameter and v(D) is the vertical component of particle velocity. The second moment of N(D) is estimated by optical extinction analysis of the Apollo cockpit video. Because of the similarity between mass erosion rate of soil as measured by optical extinction and rainfall rate as measured by radar reflectivity, traditional NWS radar/rainfall correlation methodology can be applied to the lunar soil case where various S(D) models are assumed corresponding to specific lunar sites.
4
EN
Significant amount of emitted light from an organic light emitting diode (OLED) is trapped as a result of total internal reflection (TIR) on a glass–air interface. One of the strategies to increase the light extraction efficiency is using a scattering thin film. A model is built using the Monte Carlo ray tracing method to simulate Mie scattering. Almost 100% of light trapped by the TIR can be extracted if the radius of the spherical scatters, the refractive index ratio between the matrix and the scatter and the concentration of the scatter are optimized. The implication is important for a high efficiency OLED used in the next generation lighting source.
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