Другие журналы
|
scientific edition of Bauman MSTUSCIENCE & EDUCATIONBauman Moscow State Technical University. El № FS 77 - 48211. ISSN 1994-0408![]()
Power Machine Building, Metallurgical Machine Building and Chemical Engineering
Influence of u/C0 ratio on Unsteady Loads and Efficiency Level of Axial Turbine Stage
# 06, June 2015 DOI: 10.7463/0615.0786614 pp. 56-66
Comparison of Turbulence Models in Simulation of Flow in Small-Size Centrifugal Compressor
# 06, June 2015 DOI: 10.7463/0615.0778604 pp. 67-82
Experimentally Studied Thermal Piston-head State of the Internal-Combustion Engine with a Thermal Layer Formed by Micro-Arc Oxidation Method
# 05, May 2015 DOI: 10.7463/0515.0774148 pp. 115-125
Dynamics Analysis of Frequency-Controlled Volumetric Hydraulic Drive with Power Supplied from the Built-in Pneumatic-Hydraulic Accumulator
# 03, March 2015 DOI: 10.7463/0315.0759683 pp. 15-35
Mathematical Model of Pumping Gas Process by the Cylindrical Molecular Vacuum Pump in the Wide Range of Pressures
# 12, December 2014 DOI: 10.7463/1214.0748304 pp. 200-209
Effect of the Geometric Shape of the Jet Pump Nozzle on Its Characteristics
# 12, December 2014 DOI: 10.7463/1214.0743907 pp. 210-219
Defining Rotor-Stator Clearance of Viscous Molecular Vacuum Pump by Numerical Methods
# 11, November 2014 DOI: 10.7463/1114.0743690 pp. 157-169
Conduction of Complex Elements of Vacuum Systems in a Wide Range of Pressures
# 12, December 2014 DOI: 10.7463/1214.0742647 pp. 232-241
Analysis of Factors Determining the Helmholtz Resonator Eigenfrequency
# 12, December 2014 DOI: 10.7463/1214.0742764 pp. 220-231
Object-Oriented Approach to Modeling Units of Pneumatic Systems
# 11, November 2014 DOI: 10.7463/1114.0739862 pp. 170-187
Vacuum arc on the polycrystalline silica cathode
# 11, November 2014 DOI: 10.7463/1114.0748209 pp. 188-197
Investigation of Two-Phase Flow in Axial-Centrifugal Impeller by Hydrodynamic Modeling Methods
# 09, September 2014 DOI: 10.7463/0914.0725724 pp. 45-64
Spanwise Distribution of Energy Losses in Steam Turbine Last Stage Nozzle
# 06, June 2014 DOI: 10.7463/0614.0712815 Gas-dynamic calculations of the last LPC stage of powerful steam turbine are performed with two alternative shapes of last stage nozzle using the Numeca Fine Turbo software. To compare a nozzle with combined lean (option B) to that of with straight trailing edge (option A) the article offers the method for calculating a distribution of kinetic energy losses in last stage nozzle using the Numeca CFView software package. The method is based on the calculation of loss coefficients for the single streamlines in the meridional plane. The difference between the local coefficients of kinetic energy losses calculated by the proposed method from the experimental results was 0.5 %. The use of the combined lean (option B) led to a change in the distribution of mass flow rate, pressure gradient, and steam flow rotation angles and tilt adjustment in height in the test section, which follows the last stage nozzle. As compared to the option A, for the option B in the zone a reactivity has increased by 20%, the Mach number has decreased from 1.4 to 1.2, a level of kinetic energy losses for the option B was 5.2 % that is lower than for the option A by 1.6% with the same consumption of steam flow. The greatest local decrease of kinetic energy losses for the option B was 2.5 % as compared to the option A due to decreasing intensity of the secondary flows in the shroud region. A relative efficiency of the stage with the guide (nozzle) apparatus B has increased by 1.75 % as compared to the initial option A owing to reducing losses of kinetic energy in the guide apparatus and changing conditions of the flow at the inlet of the bucket.
Optimization of Design of Steam Turbine Exhaust Conduits
# 02, February 2014 DOI: 10.7463/0214.0699887 Research aims are to decrease the hydraulic resistance of exhaust conduit of steam turbine, reduce the flow irregularity at the conduit outlet, and equalize the steam flow before the condenser tube bundle. The conduit models and flows in it have been simulated in Solid Works environment and its COSMOS Flo Works application. The article presents the research results for the initial conduit model and modified design versions. To evaluate a degree of flow irregularity the momentum factor (Bussinesku factor) has been calculated for outlet cross-section of the selected conduit design. The analyzed research results made it possible to find an optimum design of the exhaust conduit. Introducing the suggested alterations in the conduit design will enable to improve heat exchange in condenser, to increase reliability of the tube bundle operation, to decrease noise and power losses as well as to rise turbine plant efficiency in general.
Renkin's organic cycle and its application in alternative power engineering
# 02, February 2014 DOI: 10.7463/0214.0699165 The paper reviews some important aspects concerning the low-potential energy utilization using so- called organic Rankine cycle (ORC). The recent increasingly frequent applications of ORC are as follows: thermal waste treatment in industries, thermal power of combustion engines, solar and geothermal power engineering, biomass energy, etc. Significant attention is given to issues of working fluid selection. There is a list of the most important requirements for the working fluid. The paper presents the analysis of references, which examine different aspects of ORC applications and reviews the possibilities of ORC modeling.
Investigation of optical disruptive discharges in complex gaseous mixtures
# 12, December 2013 DOI: 10.7463/1213.0669474 Optical, electrical and combined electro-optical thresholds of disruptive discharges for noble gases, their binary and triple mixtures of different compositions were experimentally evaluated. The possibility of mutual reduction in discharge thresholds at a simultaneous optical and electrical impact on gas was studied along with the possibility of reduction in thresholds of a combined discharge when basic gas has additions of another gas are made. It was shown that reduction in the threshold of an optical discharge in the presence of an electric field was quite significant at low pressures. For the first time mutual suppression (negative interference) of gaseous dopants’ effect on changes in discharges’ thresholds (both optical and electro-optical) in case of triple gas mixtures was demonstrated.
Optimization of an electrohydraulic actuator for a servo drive with throttle control
# 12, December 2013 DOI: 10.7463/1213.0637872 The paper presents a problem-solving procedure for selecting parameters of an electrohydraulic actuator in order to reduce response time and hydraulic power consumption. To perform such optimization design variables of an electrohydraulic servo drive were selected; objectives were proposed to estimate design alternatives. An example of two-criterion optimization of a servo drive with throttle control was presented. These criteria were control flow and response time. Multi-objective modification of a genetic algorithm was used to obtain a Pareto front approximation. The concept described in this paper is based on generalization of optimization methods for the electrohydraulic servo actuator known from literature references and includes new proposals on the algorithm structure
Optimization of power subsystem of electrohydraulic servo drive with throttling governing
# 11, November 2013 DOI: 10.7463/1113.0623966 This paper describes optimization of the power subsystem of an electrohydraulic servo drive with throttling governing. The electrohydraulic servo drive was considered together with an electrohydraulic power amplifier replaced by a proportional link. Variable parameters were selected and objective functions for design alternatives were proposed in order to optimize the electrohydraulic servo drive. An example of two-criterion optimization of the power subsystem was considered in this paper. These criteria were nearness of phase-response characteristic to the axis of abscissae and the mass to power ratio. Multi-criterion modification of genetic algorithm was used to obtain the Pareto front. The described concept is based on generalization of optimization methods for the electrohydraulic servo drive known from literature references and includes new proposals on the structure of the optimization algorithm.
Calculation of feasibility of super high compression in the piston internal combustion engine
# 09, September 2013 DOI: 10.7463/0913.0622287 A feasibility of the four-stroke diesel engine YANMAR L-100C running under condition of the super-high compression ratio was investigated numerically in this paper. Computational model was created in the simulation modeling system “Albea” which was designed at the department of ICE of the Ufa State Aviation Technical University. Dependencies of brake efficiency on the different values of compression ratio of the investigated engine were calculated and presented in this work. It was discovered that growth of the compression ratio from 19.3 up to 30 led to the significant decrease in brake efficiency. In the meantime, decreasing of the compression ratio from 19.3 down to 12 – 15 led to the growth of brake efficiency, especially at partial loads.
Shaping of inlet ports of a diesel for conditions of high pressure charging and high pressure differentials between a collector and a cylinder
# 10, October 2013 DOI: 10.7463/1013.0617277 In this paper the authors present results of shaping a piston engine’s inlet ports. The “Large Particle” CFD method was used for simulation of a flow and estimation of the effective flow area. The investigated flow modes are characterized by high density of the incoming charge and a significant pressure fall. Diagrams of influence of geometry features on channel capacity are also given. A spatial profile of the engine’s inlet ports, including an axisymmetric part near the seat, was considered along with the diameter and location of the intake popped valve. Recommendations were given on optimal shaping of the intake ports for the promising Z-Engine.
|
|
|||||||||||||||||||||||||||||
|