Experimental and theoretical investigations of the near-ground propagation of acoustic radiation in the atmosphere

Near-ground propagation of monochromatic acoustic radiation at frequencies of 300, 1000, 2000, and 3150 Hz along atmospheric paths up to 100 m long is investigated experimentally and theoretically depending on altitudes of the acoustic source and receiver. The experiment was carried out at the experimental site of the Institute of Monitoring of Climatic and Ecological Systems (IMCES) using a specially developed setup. The dependence of the recorded sound pressure level on the propagation path length and initial signal power is analyzed. The theoretical analysis is performed by the Monte Carlo method using the local estimation algorithm developed by the authors. The comparison of the experimental and theoretical results shows their satisfactory agreement, which indicates the effectiveness of the proposed algorithm and its applicability to predicting the near-ground sound propagation

Assessment of the Technical Condition of Electric-Controlled Diesel Injectors According to the Fuel Supply Characteristics

Introduction. Currently, there are no widely available technologies and equipment available at service stations and repair facilities to accurately assess the technical condition of Common Rail battery fuel supply system injectors. The methods implemented in practice mainly give a generalized assessment of the nozzle performance without identifying a specific defect, which entails an unjustified replacement of still working parts of electrically controlled injectors. The purpose of this article is to familiarize a wide range of specialists with a new non-slip test method for injectors with electronic control based on the evaluation of their fuel supply characteristics, which allows identifying specific malfunctions of the nozzle during the procedure of diagnostic without disassembling. Materials and Methods. The study is based on a systematic analysis of the factory methods for testing injectors, a review of modern scientific publications, the use of computer simulation in specialized programs, and experimental testing of the obtained results. Results. A method for testing and evaluating the technical condition of diesel injectors based on the fuel supply characteristics has been developed and tested that can significantly increase the information content of the diagnostic and reduce the overall labor intensity of repairing electronically controlled injectors by 24%. Discussion and Conclusion. The authors have developed and tested a measurement module and a test procedure for diesel injectors with the ability to assess the technical condition of their parts, which allows identifying and eliminating specific malfunctions of injectors without disassembling them and avoid unjustified replacement of serviceable elements during repair. The results of the study have been implemented in the Bosch Diesel Service fuel equipment repair center of Bashdiesel LLC

Numerical investigation of a moisture wave-type vane separator

This study aims to determine the appropriate method for modeling separation processes in wave-type moisture vane separators and to analyze possible design improvements of the typical wave-type vane separator using numerical simulation methods. It discusses conditions of the secondary droplets generation phenomena. The applicability of the particle transport method for modeling the working process in wave-type vane separators is confirmed. The study explores the water droplets distribution pattern in the dispersed two-phase flow of a separator. A numerical study of the workflow in the typical steam-water separator with wave-type vanes was carried out. A dispersed two-phase flow in a separator is modelled as two separate flows. Dry saturated steam is considered as a continuous medium using the Euler method; the liquid phase is represented as a stream of water droplets described by the Lagrange method. Authors propose an option of modernization of the separator design applying three drainage channels on the path of small droplets

A Study of Directional Patterns of Ultrasonic Parametric Array

The paper presents results of numerical calculations and experimental data on the directional pattern of two 38-element parametric arrays composed of ultrasound sources. Two types of antenna arrays are considered, namely with parallel and coaxial connections of ultrasonic transducers (elements). The results of selecting and functional testing of unit elements are described in this paper. It is found that in the coaxial element connection of the antenna array, the level of side lobes is higher than that in the paralel element connection

Experimental and theoretical investigations of the near-ground propagation of acoustic radiation in the atmosphere

Near-ground propagation of monochromatic acoustic radiation at frequencies of 300, 1000, 2000, and 3150 Hz along atmospheric paths up to 100 m long is investigated experimentally and theoretically depending on altitudes of the acoustic source and receiver. The experiment was carried out at the experimental site of the Institute of Monitoring of Climatic and Ecological Systems (IMCES) using a specially developed setup. The dependence of the recorded sound pressure level on the propagation path length and initial signal power is analyzed. The theoretical analysis is performed by the Monte Carlo method using the local estimation algorithm developed by the authors. The comparison of the experimental and theoretical results shows their satisfactory agreement, which indicates the effectiveness of the proposed algorithm and its applicability to predicting the near-ground sound propagation