Unsteady Gas Flow Research Articles

Interaction of a Dense Layer of Solid Particles with a Shock Wave Propagating in a Tube

A numerical simulation of an unsteady gas flow containing inert solid particles in a shock tube is carried out using the interpenetrating continuum model. The gas and dispersed phases are characterized by governing equations that express the concepts of mass, momentum, and energy conservation as well as an equation that shows the change of the volume fraction of the dispersed phase. Using a Godunov-type approach, the hyperbolic governing equations are solved numerically with an increased order of accuracy. The working section of the shock tube containing air and solid particles of various sizes is considered. The shock wave structure is discussed and computational results provide the spatial and temporal dependencies of the particle concentration and other flow quantities. The numerical simulation results are compared with available experimental and computational data.

Effect of Blade Material of Steam Turbine Rotor on Aeroelastic Characteristics

Elements of powerful steam turbines are subjected to significant unsteady loads, in particular the rotor blades of the last stages. These loads, in some cases, can cause self-excited oscillations, which are extremely dangerous and have a negative impact on the efficiency and service life of the blade cascade. Therefore, when designing new or modernizing existing steam turbine stages, it is recommended to study the aeroelastic characteristics of the blades. The conditions for the occurrence of self-excited oscillations are influenced by both the geometric characteristics and the alloy from which the blade is made. To determine the effect of the blade material on the aeroelastic behaviour, a numerical analysis of the aeroelastic characteristics of the last stage blades made of steel and titanium alloy was performed. For the analysis, the method of simultaneous modeling of unsteady gas flow through the blade cascades and elastic vibrations of the blades (coupled problem) was used, which allows obtaining the amplitude-frequency spectrum of the interaction of unsteady loads and blade vibrations. The paper presents the results of numerical analysis for harmonic oscillations with a given amplitude and a given inter-blade phase angle, as well as for the regime of coupled vibration of blades under the action of unsteady aerodynamic forces. The dependences of the aerodamping coefficient on the inter-blade phase angle and the distribution of the coefficient along the blade are presented. The results of modeling the coupled vibration of the blades for the first six natural forms are presented in the form of a time-evolving displacement of the blade peripheral section, as well as forces and moments acting on the peripheral section. The corresponding amplitude-frequency spectra of displacements and loads in the peripheral section are also presented. The analysis of the results showed an insignificant difference in the characteristics of the proposed blade materials. For the first natural form of blade oscillations, the possibility of self-excited oscillations was found, and for the second form, there are conditions for the appearance of stable self-oscillations.

Withdrawn: Transient modeling of natural gas in pipeline networks by two non-iterative explicit and implicit finite volume methods

This paper describes two non-iterative explicit and implicit finite volume methods (FVM) to calculate the unsteady characteristics of natural gas in distribution systems. The proposed finite volume model could be used to solve the gas network as a whole for each time step. The main advantage of this approach is that it can analyze gas distribution networks with less computational cost. In addition, contrary to the conventional iterative algorithms, it does not consist of any divergence problems (Elman et al., 1996). To achieve this goal, the explicit FVM is derived from the governing equations. Then, the linearization process is performed, and the numerical solution of the linear equations is developed by using the implicit FVM. Three classic test cases are exemplified to check the performance of the proposed methods. The results confirm that both explicit and implicit methods, even in complicated distribution networks, can predict the elements of unsteady natural gas flows. Furthermore, when the governing equations are linearized and the implicit FVM is applied, satisfactory results with less computational cost, compared to the explicit one, are produced.

Calculation of Four-Dimensional Unsteady Gas Flow via Different Quadrature Schemes and Runge-Kutta 4th Order Method

Calculation of Four-Dimensional Unsteady Gas Flow via Different Quadrature Schemes and Runge-Kutta 4th Order Method

Simulation of interaction of a vortex ring with a normally located flat target

The need to develop models and methods for calculating unsteady gas and fluid flows with concentrated vorticity is determined by the wide distribution of such flows in nature and technology. Numerical simulation of the formation of a vortex ring, its propagation and interaction with a flat target oriented normal to the direction of movement of the ring is considered. The construction of a model of a virtual generator of vortex rings and the choice of a set of parameters describing the generating pulse (pulse duration and its amplitude) are discussed. The computational domain consists of the internal region of the vortex ring generator and the external space region behind its outlet, in which the formation and movement of the vortex ring occurs. For numerical calculations, unsteady Navier–Stokes equations in an axisymmetric formulation are used, for discretization of which the finite volume method is applied. To simulate the flow generated by the movement of the piston in the tube, unsteady boundary conditions are used at the outlet of the generating tube, describing the distribution of mass flow rate over time. The distribution of pressure over the target and the change in the longitudinal force acting on the target over time, as well as the change in the characteristics of the vortex ring during its interaction with the target are given. The results of numerical calculations are compared with the data of a physical experiment. A qualitative pattern of the flow that occurs when a vortex ring approaches a wall is presented, and the key features of the flow and critical points that are formed during the interaction of the vortex ring with the wall are discussed.

Explanation of the mechanisms of unsteady gas flow through the turbocharger seal system, including thermal and structural interactions

Gas flow in the seal system can be expected during the operation of a turbocharger and is associated with negative effects on the quality of the lubricant or turbocharger efficiency. Gas flow also affects particulate matter production due to lubricant entrainment in the compressor or turbine. The prediction of gas flow rates depends on many design parameters and the operating conditions of the turbocharger, but sufficiently accurate descriptions of the gas flow mechanisms and their quantification depending on the operating conditions have not yet been presented. The proposed computational approach simultaneously solves the gas dynamics in the seal system, the heat transfer in the turbocharger rotor-bearing system and the dynamics of the seal rings and rotor, including the bearings. The computational model for the turbocharger of a heavy-duty vehicle engine is experimentally validated. Two mechanisms have major influences on gas mass flow: the gas flow through the thin gap between the moving ring and groove and the flow through the ring gap. The results show that the importance of these mechanisms depends on several geometrical dimensions of the seal system and the operating conditions of the turbocharger, with a strong connection to the rotor dynamics and thermal load of the impellers. Influences involving rotor movement or rotor thermal conditions are crucial, and their non-inclusion limits the ability to correctly predict gas mass flow.

Numerical solution of the control problem on the depletion of gas reservoirs with weakly permeable top

The current stage in the development of mathematical and software support for the processes of designing the development of hydrocarbon fields is characterized not only by the improvement of the means of geological and hydrodynamic modeling of reservoir fluid filtration but also by the use of algorithms for optimizing the development of gas deposits. The paper considers the problem of optimal control of the depletion of a gas reservoir with a low-permeability top. Using the so-called Myatiev-Girinsky hydraulic scheme, a two-dimensional equation describing the unsteady gas flow in a reservoir with a jumper is averaged over the capacity of the productive reservoir. This comes down to a one-dimensional equation with an additional term, taking into account gas-dynamic relationships between the reservoir and the jumper. For the numerical solution of process control problems, a formula for the gradient of the functional characterizing the reservoir depletion is found, and the method of successive approximations based on Pontryagin’s maximum principle is applied. In this case, the direct and conjugate boundary value problems are solved by the method of straight lines, and the required flow rate, without taking it beyond the maximum and minimum possible, is found by the gradient projection method with a special choice of step. A brief block diagram of the algorithm for solving the problem is shown; on its basis, a computer program was compiled. The results of calculations are presented to identify the influence of the values of the complex communication parameter not only on the state of the object but also on the operating mode of the well. The expediency of using the presented optimization tool is dictated by an increase in the share of deposits

Methodology for improving the mechanical and operational properties of aircraft structural elements during its maintenance using gas pulse treatment

A methodology has been developed to ensure airworthiness by improving the reliability of structural elements of aviation and airfield equipment, which differs from the currently available ones by using new effective non-deformational technologies based on pulsating subsonic gas flows during all types of maintenance and repair. New technologies have been developed to improve the mechanical and operational properties of aircraft structural elements, applicable in the production of aviation equip-ment, in the process of its maintenance and repair, characterized by the ability to increase them in a complex, without deterioration of any parameters. The nature of the impact of unsteady subsonic gas flows on the structure and properties of aircraft structural elements made of metal and polymer materials, the stress states of products, and the corresponding physical model has been created. It is proposed to implement measures for the use of new non-deformational technologies for restoring operational properties, as well as improving the reliability and extending the life cycle of elements, parts and assemblies of aircraft, airfield equipment by transport companies that exceed the currently used efficiency, efficiency and envi-ronmental friendliness, making appropriate changes to the maintenance and repair regulations. The direction of improving the methodology for forecasting the technical condition of aircraft structural elements is indicated, which differs from the existing ones by taking into account data on the density of crystal structure defects in surface layers.

Speeding up soft pneumatic actuators through pressure and flow dynamics modeling and optimization

Soft pneumatic actuators (SPAs) possess the potential to be used in various scenarios due to the softness of their compositional materials to generate various modes of motion. The actuation frequency of SPAs is commonly in the range of 0-4 Hz, limiting their applications only to normal-speed tasks. To reveal the key affecting factors to the actuation speed and further optimize an SPA’s response speed for more dynamic applications, a predictive model of the whole pneumatic supply system (PSS) that takes the pressure and flow dynamics into consideration is needed. In this work, we introduce a comprehensive pressure and flow dynamic model of high-speed PSSs and SPAs. Here, the PSS is regarded as a compressed air source and a volume-fixed reservoir that are connected by a tube. The pressure and flow dynamic is modeled by correcting the adiabatic model to account for real heat exchange, and considering the assumptions of steady state of the gas flow through an orifice and the one dimensional unsteady gas flow in the tube. After calibration and validation with experiment results, we investigated the key affecting factors of PSSs on the attainable frequency of the SPA, which provides the design guidelines for the high-speed PSSs. Results show that the PSS with pure helium is dramatically faster than that with air. Finally, we present a demonstration of a helium-PSS actuated fiber-reinforced, bending SPA that achieves high frequency of up to 39 Hz in its blocked force.

Magneto-radiative gas near an unsmooth boundary with variable temperature

PurposeThis paper aims to study the magneto-radiative gas (water vapor) on an unsmooth boundary.Design/methodology/approachThis paper provided a numerical treatment via the implicit Chebyshev pseudo-spectral method to investigate unsteady compressible magneto-radiative gas (water vapor Pr = 1) flow near a heated vertical wavy wall through porous medium in the presence of inclined magnetic field. The impacts of viscous dissipation, temperature-dependent fluid properties, thermal conductivity and viscosity in the presence of nonlinear thermal radiation are studied. The sinusoidal surface is transformed into a flat one using a suitable transformation. The comparison figures of published data with the present outcomes illustrate a good match. The present steady-state outcomes are presented for the temperature, velocity, Nusselt number and the shearing stress through figures for several interested physical parameters, namely, compressibility, magnetic, radiation, viscosity–temperature variation, thermal conductivity–temperature variation, surface sinusoidal waveform and porous parameters.FindingsThe present numerical outcomes confirm the importance of applying nonlinear thermal radiation cases in all studies that investigate heat transfer under the influence of thermal radiation.Originality/valueA mathematical model is established for a wavy boundary, and Chebyshev pseudo-spectral method is adopted for the numerical study.

Spectral analysis of gas-dynamic characteristics of pulsing gas flows in the exhaust system of a piston engine

THE PURPOSE. To On the basis of spectral analysis, to evaluate the effect of installing a turbocharger turbine on the aeromechanics of pulsating gas flows in the engine exhaust system and to propose a method for controlling the aerodynamic and heat transfer characteristics of unsteady gas flows by creating an ejection effect in the exhaust system.METHODS. A laboratory experiment on a full-scale piston engine model was chosen to achieve this goal. Spectral analysis of harmonic dependences was used to assess changes in the structure of gas flows in the exhaust system. Mathematical modeling of the operating cycle of diesel engines was used to assess the potential positive effects of the use of an ejection system in the exhaust tract of a diesel engine. Three-dimensional solid modeling systems were used for sketch (engineering) studies of new (modernized) exhaust system designs.RESULTS. The article describes laboratory equipment, measuring system and data processing methods. A description of the boundary conditions in the course of experimental research is given. Comparison of aeromechanical and heat exchange characteristics of unsteady flows in the exhaust system of an engine with and without a turbocharger is carried out in the article. The qualitative and quantitative differences in aeromechanics and thermal physics of processes are shown. The proposed method of aeromechanical improvement of the exhaust system by creating an ejection.CONCLUSION. It was revealed that the turbine of a turbocharger has a significant effect on the aeromechanical characteristics of flows in the exhaust system. A significant decrease in the maximum flow rate in the exhaust tract (up to 3 times) is observed when installing a turbocharger. There is a decrease in flow characteristics through the turbocharged exhaust system (within 30%). It was found that the ejection effect in the engine exhaust system leads to stabilization of the flow, an increase in gas consumption by 6-12%, a decrease in specific fuel consumption by an average of 1% and an improvement in reliability indicators by 1.11-1.74%.

Selected Mathematical Models Describing Flow in Gas Pipelines

The main aim of simulation programs is to study the behavior of gas pipe networks in certain conditions. Solving a specified set of differential equations describing transient (unsteady) flow in a gas pipeline for the adopted parameters of load and supply will help us find out the value of pressure or flow rate at selected points or along selected sections of the network. Transient gas flow may be described by a set of simple or partial differential equations classified as hyperbolic or parabolic. Derivation of the mathematical model of transient gas flow involves certain simplifications, of which one-dimensional flow is most important. It is very important to determine the conditions of pipeline/transmission network operation in which the hyperbolic model and the parabolic model, respectively, should be used. Parabolic models can be solved numerically in a much simpler way and can be used to design simulation programs which allow us to calculate the network of any structure and any number of non-pipe elements. In some conditions, however, they describe the changes occurring in the network less accurately than hyperbolic models do. The need for analysis, control, and optimization of gas flows in high-pressure gas pipelines with complex structure increases significantly. Very often, the time allowed for analysis and making operational decisions is limited. Therefore, efficient models of unsteady gas flows and high-speed algorithms are essential.

Метод интегральных уравнений Вольтерра в исследовании динамики самогравитирующего газа, ограниченного свободной поверхностью

The paper investigates dynamics of the finite mass of self-gravitating ideal gas with a variable flow bounded by free surface. Unsteady gas flows are described by a phenomenological mathematical model of gas dynamics, which is constructed using a system of nonlinear integral-differential equations written in Eulerian coordinates. The gas motion is considered under the condition that the free boundary at all times consists of the same particles. This circumstance makes it convenient to switch from Eulerian coordinates to Lagrangian coordinates, for which the domain of determining the solution of the gas motion problem will be fixed in advance. The transformation of the system to Lagrangian coordinates makes it possible to reduce it to an equivalent system consisting of Volterra-type integral equations and the continuity equation in Lagrangian form, and get rid of the unknown boundary. Using the method of successive approximations, properties of compact spaces, a series of original and specific estimates found for functions describing the flows of the self-gravitating gas, convergence of a sequence of approximate solutions is proved under assumptions about smoothness of the initial data. The theorem of existence and uniqueness of the solution of the Cauchy problem for the system of integral equations of the Volterra type is proved, and, consequently, the solution of the desired problem is found within the framework of the assumptions made about the motion in vacuum of the isolated mass of the self-gravitating ideal gas with a variable flow domain.

Maximizing volumetric efficiency using stochastic optimization techniques for internal combustion engines

The volumetric efficiency of internal combustion engines quantifies the effectiveness of the admission process, whereas the thermal efficiency quantifies the amount of work generated based on the total energy released by the fuel. A method to optimize these efficiencies is by changing the valve timing. In this study, the parallelized particle swarm optimization method is implemented to maximize the volumetric efficiency, and its performance is compared with the differential evolution method. Calculations are performed using a parallelized computational code comprising a one-dimensional model for unsteady compressible gas flow in the intake and exhaust ducts, a single-zone combustion model for the in-cylinder process, and optimization routines based on particle swarm optimization and differential evolution techniques. In both optimizations, the design variables are the opening and closing angles of the intake and exhaust valves. Both optimization methods reach the same maximum volumetric efficiency, but the particle swarm optimization presents a smaller deviation from the mean values and better performance in terms of computational time. In addition, a higher volumetric efficiency is associated with higher values of the exhaust valve opening angle and intake valve closing angle at speeds of 2000 and 3000 rpm, respectively. Finally, it can be concluded that both optimization methods can optimize the volumetric efficiency and reach the same maximum value; however, the particle swarm optimization performs better in terms of the computational time and exhibits fewer deviations from the mean values.

A 1D–3D Approach for Fast Numerical Analysis of the Flow Characteristics of a Diesel Engine Exhaust Gas

It is necessary to analyze the intake/exhaust gas flow of a diesel engine when turbocharger matching and when installing emission control devices such as exhaust gas recirculation (EGR), selective catalytic reduction (SCR), and scrubbers. Analyzing the intake/exhaust gas flow using a 3D approach can use various analytical models, but it requires a significant amount of time to perform the computation. An approach that combines 1D and 3D is a fast numerical analysis method that can utilize the analysis models of the 3D approach and obtain accurate calculation results. In this study, the flow characteristics of the exhaust gas were analyzed using a 1D–3D coupling algorithm to analyze the unsteady gas flow of a diesel engine, and whether the 1D–3D approach was suitable for analyzing exhaust systems was evaluated. The accuracy of the numerical analysis results was verified by comparison with the experimental results, and the flow characteristics of various shapes of the exhaust system of a diesel engine could be analyzed. Numerical analysis using the 1D–3D approach was able to be computed about 300 times faster than the 3D approach, and it was a method that could be used for research focused on the exhaust system. In addition, since it could quickly and accurately calculate intake/exhaust gas flow, it was expected to be used as a numerical analysis method suitable for analyzing the interaction of diesel engines with emission control devices and turbochargers.

Method for Calculating Transients in a Gas Pipeline

Abstaract. An analytical solution of a system of partial differential equations describing the unsteady isothermal flow of real gases in gas pipelines is considered. Such a problem arises when studying the regularity of alterations in the instantaneous values of pressure and gas flow in main gas pipelines, for example, during startups and shutdowns of large gas consumers. Meanwhile, transients are not necessarily of a pronounced oscillatory nature, despite the fact that they are described by periodic functions. In the course of the research, the task was set to obtain a mathematical model of the process taking into account the inertial term of the equation of motion, the neglect of which is possible only if the friction losses are exceeded by 3.5–4 times over the shock pressure. An important feature of the solution that have been found is its universality, which makes it possible to significantly reduce labor costs when using it to find partial solutions to practical problems that differ in boundary conditions. The boundary conditions of the first kind are given as an arbitrary function of both the gas flow rate and its pressure. The solution is based on the widely used method of separation of Fourier variables. In order to simplify the calculations, the original differential equation is transformed in such a way that the boundary conditions acquire the property of homogeneity. It has been determined that the requirements that the boundary conditions are equal to zero at the initial moment of time introduced into the solution make it possible to obtain a concise record of the obtained analytical model, but do not limit the area of the use of the model with a surge change in the gas flow rate or pressure. The obtained analytical model of unsteady gas flow makes it possible, without using the Duhamel integral, to find analytical solutions under more complex boundary conditions than the flow rate jump. At the same time, the solutions found completely coincide with the solutions based on the Duhamel integral, but in the course of the solution that we have found it is possible to avoid integration, which has a positive effect on the applicability of this approach in the practice of engineering calculations.

Influence of gas transmission network failure on security of supply

This paper investigates the influence of failure of transmission network key elements on security of natural gas delivery. The proposed framework combines the probabilistic structure integrity study and the hydraulic analysis. A factor called a volumetric loss was introduced to quantify the effect of network failure. Based on the magnetic flux leakage diagnostics, the rupture probability of steel tube plastic collapse was estimated using a random variable method and Monte Carlo solution. In-line inspections should monitor only the rate of tube wall corrosion, whereas the proposed methodology enables the pipeline operator to evaluate the system ability to deliver gas at the customer nodes. For the hydraulic analysis, an unsteady gas flow model was applied using conservation principles of mass, momentum, and energy. The flow model was tuned to real pressure and temperature data using a multi-objective optimization approach. To demonstrate the practical value of the methodology, the time and amount of gas shortage, line pack, and a volumetric loss were computed for a real tree-topological pipeline network. Simulations demonstrated that the highest volumetric loss is experienced when both compressor stations are shut down. The aim of the proposed algorithm is identification of critical nodes as well as evaluation of measures for improving the gas supply reliability to the customers.

Nusselt correlation development in unsteady laminar gas flows for CABRI multiphysic simulations with CATHARE2

CABRI is an experimental pulse reactor, which aims at studying and thus at better understanding RIA (Reactivity Initiated Accident) effects on nuclear fuels. The restart of the CABRI reactor in 2015 offers the opportunity to validate tools involving multiphysic calculation schemes on reactivity insertions (RI) transients at a system scale. The reactivity insertion in CABRI is mastered by the depressurization of a neutron absorber (3He), contained into transient rods. This enables the realization of various types of transients. As this depressurization highly influences the reactivity insertion kinetics, it is essential to accurately simulate the 3He density evolution which depends on the heat exchanges inside the circuit. The challenge is thus to manage the simulation of the various CABRI complex transients. Previous work allowed to model with CATHARE2 the whole reactor with its specific phenomena as well as phenomena generally involved in RIA, for instance strong neutronic feedback effects, effect of the pellet-clad interaction on the gap conductance and transient heat exchanges between fuel rods and water. These studies also revealed that some CABRI transients were still difficult to model with CATHARE2 and this paper shows the necessity to catch the transient heat exchanges in the transients rods for the simulation of the power pulse in CABRI reactor. In order to achieve this objective, a correlation for the Nusselt evolution in an unsteady compressible laminar 3He flow, inside a closed tube, has been realized from numerical resolution of an analytical model and implemented in the scientific calculation tool CATHARE2. This paper describes this analytical model and its numerical resolution. After having been validated on results of the literature in steady flow inside open tube, the correlation established for the evolution of the Nusselt in a transient rods’ tube is given. Finally, Best-Estimate simulation results of CATHARE2 are compared with experimental data obtained on CABRI commission tests: core power and 3He pressure evolution.

Численное исследование нестационарного течения газа в камере сгорания прямоточного воздушно-реактивного двигателя с учетом процесса теплообмена

Проведено численное исследование нестационарного турбулентного сверхзвукового течения в камере сгорания прямоточного воздушно-реактивного двигателя. Описана методика экспериментального измерения температуры на стенке осесимметричного канала в камере сгорания двигателя. Математическое моделирование обтекания исследуемой модели двигателя проводилось для скоростей набегающего потока M = 5 ... 7. Начальные и граничные условия задачи соответствовали реальному аэродинамическому эксперименту. Проанализированы результаты численного расчета. Рассмотрено изменение распределения температуры вдоль стенки канала с течением времени. Проведена оценка согласованности полученных экспериментальных данных с результатами математического моделирования. Purpose. The aim of this study is a numerical simulation of unsteady supersonic gas flow in a working path of ramjet engine under conditions identical to aerodynamic tests. Free stream velocity corresponding to Mach numbers M=5 ... 7 are considered. Methodology. Presented study addresses the methods of physical and numerical simulation. The probing device for thermometric that allows to recording the temperature values along the wall of internal duct was proposed. To describe the motion of a viscous heat-conducting gas the unsteady Reynolds averaged Navier - Stokes equations are considered. The flow turbulence is accounted by the modified SST model. The problem was solved in ANSYS Fluent using finite-volume method. The initial and boundary conditions for unsteady calculation are set according to conditions of real aerodynamic tests. The coupled heat transfer for supersonic flow and elements of ramjet engine model are realized by setting of thermophysical properties of materials. The reliability testing of numerical simulation has been made to compare the results of calculations and the data of thermometric experimental tests. Findings. Numerical simulation of aerodynamic tests for ramjet engine was carried out. The agreement between the results of numerical calculations and experimental measurements for the velocity in the channel under consideration was obtained; the error was shown to be 2%. The temperature values were obtained in the area of contact of the supersonic flow with the surface of the measuring device for the external incident flow velocities for Mach numbers M = 5 ... 7. The process of heating the material in the channel that simulated the section of the engine combustion chamber was analyzed. The temperature distribution was studied depending on the position of the material layer under consideration relative to the contact zone with the flow. Value. In the course of the work, the fields of flow around the model of a ramjet engine were obtained, including the region of supersonic flow in the inner part of axisymmetric channel. The analysis of the temperature fields showed that to improve the quality of the results, it is necessary to take into account the depth of the calorimetric sensor. The obtained results will be used to estimate the time of interaction of the supersonic flow with the fuel surface required to reach the combustion temperature.

Edge Detection and Machine Learning Approach to Identify Flow Structures on Schlieren and Shadowgraph Images

Schlieren, shadowgraph and other types of refraction-based techniques have been often used to study gas flow structures. They can capture strong density gradients, such as shock waves. Shock wave detection is a very important task in analyzing unsteady gas flows. High-speed imaging systems, including high-speed cameras, are widely used to record large arrays of shadowgraph images. To process large datasets of the high-speed shadowgraph images and automatically detect shock waves, convective plumes and other gas flow structures, two computer software systems based on the edge detection and machine learning with convolutional neural networks (CNN) were developed. The edge-detection software utilizes image filtering, noise removing, background image subtraction in the frequency domain and edge detection based on the Canny algorithm. The machine learning software is based on CNN. We developed two neural networks working together. The first one classifies the image dataset and finds images with shock waves. The other CNN solves the regression task and defines shock wave position (single number) based on image pixels tensor (3-D array of numbers) for each image. The supervised learning code based on example input-output pairs was developed to train models. It was shown, that the machine learning approach gives better results in shock wave detection accuracy, especially for low-quality images with a strong noise level. Software system for automated shadowgraph images processing and x-t curves of the shock wave and convective plume movement plotting was developed.