Представлені результати чисельних та експериментальних досліджень процесу нагріву алмазних бурових коронок під час буріння свердловин. Розглянуто температурні режими буріння в умовах стаціонарної і нетрадиційної технології імпульсної промивки свердловини. За результатами дослідження теплових процесів на вибою визначено параметри, які забезпечують ресурсо-та енергоефективний режим буріння при імпульсної подачі промивальної рідини Ключові слова: температурні режими, буріння, CFD моделювання, енергоефективність, імпульсне промивання Представлены результаты численных и экспериментальных исследований процесса нагрева буровых коронок при бурении скважин. Рассмотрены температурные режимы бурения в условиях стационарной и нетрадиционной импульсной промывки скважины. По результатам исследований тепловых процессов на забое определены параметры, которые обеспечивают энергоэффективный и ресурососберегающий режим буренияКлючевые слова: температурне режимы, бурение, CFD моделирование, энергоэффективность, импульсная промывка UDC 621.7:622.23

The article deals with the experimental and numerical investigation of thermal and gas dynamics processes in combustion chamber of prospective rocket engine developed in Oles Honchar Dnipropetrovsk National University (Ukraine). This engine uses slurry fuel, and the advantages of such innovative approach to rocket engines are discussed herein. The successfully tested layout design of the experimental engine is described. The mathematical model of the combustion chamber working process research is developed, and its reliability is provided. The results of experimental and numerical examination of pressure and temperature in the combustion chamber are presented. Analysis of the processes in the combustion chamber allowed the author to define the shortcomings of the experimental scheme. Directions for further improvement of the design of the described rocket engine are defined.

Purpose. To study the effect produced by the intermittent flushing on hydrodynamic processes in the hydraulic system of a diamond bit. Methods. Mathematical modeling methods and CFD experiment.Findings. A mathematical model of hydrodynamic processes in the flushing ports of the drill bit hydraulic system in conditions of drilling with intermittent flushing is presented. Numerical study of hydrodynamic processes for symmetric intermittent flushing was conducted. The velocity and pressure fields in the flow of the drilling fluid (water) in the ports were obtained. It was shown that pressure changes significantly in the flow with formation of low pressure zones and low intensity vortex during the pause in feeding. Analysis of the obtained effects shows that the use of intermittent flushing allows to control the hydrodynamic processes and influence the diamond drill bit operation.Originality. Hydrodynamics of intermittent flow of the flushing fluid in the hydraulic system of drill bits was investigated for the first time ever. The obtained results are the basis to theoretical substantiation of technological effects during drilling with intermittent flushing, such as improving bottom hole cleaning from slurry and increasing drilling speed. Practical implications.The results of the study are important for developing a technique and technology of diamond drilling with intermittent flushing.