Thermogasdynamic Effects of the Engine Turbines With the Contra-Rotating Rotors

1990 ◽  
Author(s):  
Y. V. Sotsenko
Keyword(s):  
Flow Pattern ◽  
Thermodynamic Characteristics ◽  
Experimental Investigations ◽  
Dynamic Features ◽  
Gas Dynamic

There were carried out the experimental investigations of the gas dynamic features and the analysis of the thermodynamic characteristics of the advanced engine turbines, designed with allowance for effects of the contra-rotating rotors. The investigations were performed on 12 rectilinear cascades with the different fluid deflection and meridional opening. The comparison of the obtained characteristics and the analysis of the flow pattern show the cascades for contra-rotating rotors have specific features which are necessary to take account while its designing.

scholarly journals The analysis of a diagnostic informativeness of gas dynamic parameters in a marine diesel engine turbocharging system through an entropy function

2009 ◽  
Vol 137 (2) ◽  
pp. 19-25
Author(s):  
Zbigniew KORCZEWSKI ◽  
Marcin ZACHAREWICZ
Keyword(s):  
Diesel Engine ◽  
Diagnostic Testing ◽  
Experimental Investigations ◽  
Diagnostic Purpose ◽  
Marine Diesel Engine ◽  
Spectral Correlation ◽  
Flow Process ◽  
Gas Dynamic ◽  
Marine Diesel ◽  
Entropy Functions

The article presents selected elements of the elaborated diagnostic testing method of marine diesel engine working spaces based on the energetic and spectral-correlation analysis of the course of the pulsating exhaust flow process in the channel powering a turbocharger. The investigations have been worked out within the scope of a realization of the research project No. 0T00B02129 funded by the Committee of Scientific Research. Conducting of an analysis of the diagnostic informativeness among the parameters characterizing the observed gas dynamic processes represented an essential methodological question of the project. A mathematical model, enabling simulations of well-known and recognizable engine working spaces failures as well as an entropy functions, as the measure of uncertainty of the set of identified states of the engine unfitness were applied for such a diagnostic purpose. Having evaluated the diagnostic information three diagnostic parameters were selected in the result of experiments of the numerical simulation. Thus, the adequate parameters of a technical state assessment of the marine diesel engine working spaces were chosen while there was no possibility to work out the cylinder indication (to create cylinder indicator diagrams). The conducted simulating investigations represented an introduction to the experimental investigations (to the diagnostic tests) of DETROIT DIESEL and ZVIEZDA engines that had been put into operation on the Polish Navy warships in recent years.

scholarly journals Исследования турбокомпрессоров с общим рабочим колесом для применения в двигателях и энергоустановках

2021 ◽  
pp. 33-38
Author(s):  
Владимир Анатольевич Шкабура
Keyword(s):  
Flow Pattern ◽  
Correction Factor ◽  
Power Plants ◽  
Average Diameter ◽  
Load Factor ◽  
General Criterion ◽  
Dynamic Calculation ◽  
Counter Flow ◽  
Direct Flow ◽  
Gas Dynamic

The article deals with the working processes in flowing part of the turbo-compressors with general impeller (TCG) and with two schemes of the flows. The work studies the features of the TCG operation with two schemes of the flows and the gas-dynamic calculation theory development of their flow parts for use in engines and power plants. The tasks to be solved are to investigate two schemes of the flows in the interscapular space of the impeller – direct-flow and counter-flow. If the gas and air flow directions coincide concerning the axis of rotation of the impeller, then the flow pattern in the TCG is direct-flow, with the opposite movement of flows – is counter-flow. The solution to this problem was performed using the developed methods of gas-dynamic calculation of the TCG flow parts. Conclusions. The scientific novelty of the results obtained is as follows: parameters that significantly affect the efficiency of the turbine and compressor parts of the TCG were established and the formula in the form of a general criterion ratio was calculated. The dependence of the correction factor is determined, which considers the effect of the ratio of the impeller width on the average diameter of the working channel of the RK in the compressor section and the turbine section of the TCG. The article contains formulas, with correction factors, for calculating the power factor in the compressor section and the load factor in the turbine section. If the ratio of the grating width to the average diameter of the working channel is overestimated, it is necessary to supplement the formulas with a correction factor that considers the effect of this ratio. Studies have determined that switching from one mode of operation to another – in a certain section of the impeller, accelerates the flow to the required speed. It is especially evident in the compressor working channel of the TCG with a counter-flow pattern. In the turbine section, the gas flow acceleration time does not depend on the flow pattern – the flow is active and accelerates to the required speed in the nozzle apparatus. The given formulas allow calculating the power of the turbine and compressor parts of the impeller to perform an enlarged gas-dynamic calculation of TCG. Studies have determined that TCG can be used in gas turbine engines and the pressurization system of an internal combustion engine.

Experimental Investigation on Flow Patterns of Cylindrical-Conical Spout-Fluidizing Bed

2011 ◽  
Vol 354-355 ◽  
pp. 338-343
Author(s):  
Qian Jun Li ◽  
Dong Ping Zhang
Keyword(s):  
Flow Pattern ◽  
Fluidized Bed ◽  
Fixed Bed ◽  
Ccd Camera ◽  
Flow Patterns ◽  
Operating Conditions ◽  
Hydrodynamic Characteristics ◽  
Experimental Investigations ◽  
Bed Height ◽  
Bed Materials

Experimental investigations on hydrodynamic characteristics of cylindrical pressurized spout-fluidizing bed were carried out. Two kinds of millet were used as bed materials. The operational pressure is 0.1MPa~0.4MPa (absolutely pressure). Five distinct flow patterns, i.e, fixed bed(FB), jet in fluidized bed with bubbles(JFB), jet in fluidized bed with slugging(JFS), spout with aeration(SA) and spout-fluidizing bed(SF) were identified. Effects of the static bed height and operational pressure on the flow pattern map were particularly studied. Typical flow pattern images obtained by a high- resolution digital CCD camera were presented for classifying these flow patterns. Typical flow pattern maps were plotted for describing the transitions between flow patterns with operating conditions

scholarly journals FORMATION OF THE SUPERSONIC HETEROGENEOUS STREAMS IN THE GASDYNAMIC ACCELERATORS WITH GREAT ELONGATION

2019 ◽  
Vol 16 (33) ◽  
pp. 728-735
Author(s):  
P. V. NIKITIN ◽  
L. N. RABINSKIY ◽  
O. V. TUSHAVINA
Keyword(s):  
Boundary Layer ◽  
Heat Exchange ◽  
Gas Dynamics ◽  
High Speed ◽  
Gas Flow ◽  
Classical Model ◽  
Particle Accelerator ◽  
Experimental Investigations ◽  
Axially Symmetric ◽  
Gas Dynamic

The present article describes results of the experimental and theoretical investigation of gas dynamics and heat exchange in the course of a supersonic flow of the gas-powder mixture within the axially symmetric gas-dynamic accelerators, which have small critical cross-sections (dcritical from 1 to 3 mm) and substantial elongation (L/dcritical from 70 to 200). The necessity of performance of such investigations was determined by two aspects. The first is the development of the innovative technologies with the purpose of formation of the heat-resistant coatings and other coatings with various functions and necessary properties (formation of such coatings with the help of supersonic heterogeneous streams). The second is the creation of the supersonic heterogeneous streams, which are required for the development of experimental investigations of processes of the erosive and corrosive wear of structural components of the high-speed air vehicles, which conduct flights in atmospheric anomalies (rain clouded sky and dust-in-air conditions). This study describes the entire cycle of the experimental investigations, which were performed with the purpose of construction of the more reliable mathematical model of flow of the nonisentropic heterogeneous streams in the gas-dynamic accelerators with great elongation. The viscous gas flow parameters were calculated using the classical model of a flat boundary layer. The value of the characteristics of the carrier gas flow, the dispersion of particles and their material for accelerating particles in a heterogeneous flow were found out. The study showed that the design of gasdynamic micro accelerators must be carried out taking into account the increase in the thickness of the boundary layer along the walls of the particle accelerator. In addition, this article presents a more detailed description of gas dynamics of flow and heat exchange of the heterogeneous mixtures within supersonic gasdynamic accelerators with mass concentration of the powder particles ("К-phase") in the stream up to 15%.

scholarly journals Efficient investigation on fully developed flow in a mildly curved 180° open-channel

2014 ◽  
Vol 16 (6) ◽  
pp. 1250-1264 ◽  
Author(s):  
Yuchuan Bai ◽  
Xiaolong Song ◽  
Shuxian Gao
Keyword(s):  
Secondary Flow ◽  
Flow Pattern ◽  
Turbulent Flows ◽  
Three Dimensional ◽  
Engineering Application ◽  
Experimental Investigations ◽  
Shear Stresses ◽  
Fully Developed Flow ◽  
Wall Shear ◽  
Volume Method

Turbulent flow in meandering open channels is one of the most complicated and unpredictable turbulent flows as the interaction of various forces, such as pressure gradient, centrifugal force, and wall shear stresses severely affect the flow pattern. In order to improve significance in engineering application, understanding the overall flow characteristic is the focus. This paper presents the results of numerical and experimental investigations of flow in a 180° mild bend, which is close to criticality with curvature ratio R/B = 3. Considering the characteristic of various models, three-dimensional (3D) re-normalization group (RNG) k–ε model was adopted to simulate the flow efficiently. Governing equations of the flow were solved with a finite-volume method. The pressure-based coupled algorithm was used to compute the pressure. The flow velocities were measured experimentally with Micro acoustic Doppler velocimeter. Good agreement between the numerical results and measurements indicated that RNG k–ε model can successfully predict this flow phenomenon. The flow pattern in this bend is influenced widely by the secondary flow. The variations of velocity components, streamlines, secondary flow, and wall shear stresses are analysed in the study. Some newly discovered phenomenon in this special state are worth noting.

scholarly journals On the Gas Dynamic Features of the Interacting Binary System UU Cas

2019 ◽  
Vol 883 (2) ◽  
pp. 186
Author(s):  
Dmitry A. Kononov ◽  
Stanislav Yu. Gorda ◽  
Sergey Yu. Parfenov
Keyword(s):  
Binary System ◽  
Dynamic Features ◽  
Gas Dynamic

The gas dynamics of massive evaporation and condensation

1991 ◽  
Vol 335 (1639) ◽  
pp. 487-511 ◽  
Keyword(s):  
Prandtl Number ◽  
Phase Change ◽  
Vapour Phase ◽  
Experimental Investigations ◽  
Heat Conducting ◽  
Evaporation And Condensation ◽  
Gas Dynamic ◽  
Dynamic Field ◽  
Mass Fluxes ◽  
Viscous Heat

We consider in this paper the gas dynamic field associated with liquid-vapour phase change between two parallel liquid surfaces. The full nonlinear equations for a compressible, viscous, heat conducting gas are considered with no limitations on the Mach number. First the inviscid problem is formulated and the exact solutions found for the temperature and velocity fields. While these solutions are qualitatively similar to those found using linearized analyses significant quantitative differences exist, especially at higher mass fluxes. Next the nonlinear, viscous field is obtained for a vapour with a Prandtl number of 0.75, as the equations simplify for this case. The results obtained show dramatic departures from the inviscid solutions: the temperature profiles, which may no longer be monotonic, can manifest both undershoots and overshoots. Cases exist, whose relevance to the phase change problem is yet to be established, where the overshoot is many times the applied temperature difference. Asymptotic solutions are also developed for small and large values of the height parameter §/H which show interesting features; for small heights the temperature profile is, surprisingly, quadratic in y while for large heights the flow field is uniform with boundary layers at both surfaces. The restriction on the Prandtl number is then removed. The solutions for arbitrary Prandtl number are shown to merge smoothly to the appropriate inviscid solution as Pr-> 0. These solutions also show that Pr = 3/4 is a very good approximation for most gases and vapours of interest. The remarkable predictions that have been made here show that the role of viscosity in the gas dynamic field in liquid vapour phase change has so far been vastly underestimated. The present results will necessitate serious rethinking on the inviscid, linearized theoretical framework that has so far, by and large, been used. These results will also have a serious bearing on any future experimental investigations of the phenomenon.

Conjugate Heat Transfer From a Flat Plate With Combined Impingement and Film Cooling

2012 ◽  
Author(s):  
Rajesh Kumar Panda ◽  
B. V. S. S. S. Prasad
Keyword(s):  
Flat Plate ◽  
Film Cooling ◽  
Fluid Dynamic ◽  
Impinging Jets ◽  
Experimental Investigations ◽  
Thermochromic Liquid Crystal ◽  
Dynamic Features ◽  
Conducting Material ◽  
Film Cooling Effectiveness ◽  
Combined Cooling

Computational and experimental investigations are reported on a flat plate subjected to combined impingement and film cooling with a (14 × 14) matrix of impingement holes and three (6 × 4) staggered arrays of 35° inclined film holes. Conjugate flow and thermal computations are carried out, by using shear stress transport (SST) κ-ω turbulence model. The combined thermo fluid dynamic features of impinging jets and the coolant-mainstream interactions in presence of impingement and film cooling plates are described. Local values of Nusselt number are presented on the impingement surface and film cooling effectiveness values are plotted along the interaction surface. The computed surface temperature distribution is validated by thermochromic liquid crystal measurements. A comparison between the film cooling and the combined impingement and film cooling shows that the surface effectiveness values for the combined cooling are higher as well as more uniform. As the blowing ratio is increased from M = 0.6 to 1.0, the local streamwise effectiveness values show an increasing trend for both the cases. The effectiveness values are higher for higher conducting material at all blowing ratios. However, in case of lower conducting material, local patches of higher effectiveness are observed close to the jet exit.

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