На основе результатов сейсмометрических обследований разработаны методические рекомендации по проведению обследований и мониторинга технического состояния зданий различного назначения для обеспечения их безопасной эксплуатации. В работе приведены основные требования по организации и проведению обследований и сейсмометрического мониторинга, требования к средствам измерения, программам сбора, обработки и интерпретации данных, выбору параметров регистрации колебаний. Детально рассмотрены определение динамических характеристик 1-й группы (частот и форм собственных колебаний, диссипативных характеристик, скоростей распространения упругих волн), расчёт динамических характеристик 2-й группы (упругих характеристик несущего каркаса здания и основания), оценка динамических характеристик 3-й группы (реакция на ветровую нагрузку и сейсмическое воздействие, сценарий разрушения)
Purpose. A computational valuation of the parameters of the process of commercial grade and blended fuel flow in the injector nozzle of a locomotive diesel engine, and its impact on spraying conditions in the combustion chamber. Methodology. The scientific investigation is based on using the technique of a comparative numerical experiment. Modern numerical methods in computational fluid dynamics are used for simulating fuel flow and spraying processes in the injector nozzle and combustion chamber. Findings. It was found that when working with commercial grade fuel with maximum pressure in the area of the injector well of 85MPa, the fuel flow velocity in the fuel injection nozzle hole reaches 434 m/s, whereas when working with fuel blended with alcohol the velocity decreases to 429 m/s (at a 25% alcohol concentration). Due to the lower pressure of saturated vapours of the blended fuel, as compared to that of commercial grade fuel, the fuel-air mixing conditions degrade at the operating duty being investigated. Originality. The investigation helped to study the impact of blended fuel composition on changes in the processes of its flow in the injector nozzle, and on the injection into the combustion chamber and the fuel-air mixing conditions. The study results helped to develop recommendations on ensuring effective ICE operation with blended fuel. Practical value. A change in the conditions of blended fuel spraying and fuel-air mixing should be taken into account when choosing effective fuel injection advance angles and fueling principles in order to ensure high ICE economic and ecological performance.
The article demonstrates a rational scheme of the supercharging system in a helicopter diesel engine with a power of 100 kW, regardless of the flight altitude, and proposes a method for assessing the power losses for a diesel engine depending on the flight altitude using a mathematical model. There are three variants of an engine supercharger scheme with a single-stage turbocharger, a two-stage one with parallel or sequential compressor drive and a turbo-blower. As a result of the computational analysis according to the original method, it was shown that from the point of view of the least energy consumption two-stage scheme with a compressor and a sequential drive is the most rational. To reduce energy losses in the drive with two-stage supercharging, a concept for controlling the pressure system was proposed, which includes changing the rotational speed of the compressor drive and adjusting the throttles. Simulation of the engines running during the climb / descent of the helicopter showed that the proposed pressure scheme and control concept is effective. In order to improve the quality of regulation, the possibility to use an electric drive with the first stage compressor is being considered.
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