Applied Mechanics and Materials Vols. 152-154

Abstract: Position initiation error shows great influence on new EFP. It not only causes the way of crushed liner by detonation wave at initial phase, but also influences wave front to show asymmetric. Finally it influences detonation wave collision effect to make penetrator slope. The influence of position initiation error on new EFP was studied in numerical simulation. As increase of position initiation error, tilt trend shows faster. For different length of charge, position initiation error shows different collision effect. Position initiation error shows greater influence with smaller length charge than larger.

Abstract: The configuration characteristics and actual working condition of the downhole unit of existing electrical-submersible-motor driven progressing cavity pumping (ESPCP) system are analyzed in detail. Appling the methods and the main tools of Triz theory, conflicting analysis is performed for the axial bearing capacity affecting submersible depth and operational lifespan of downhole unit. The parameters of physical and technical contradictions are standardized. Appropriate principles of invention are selected through contradiction matrix analysis and a more reasonable innovation design project of the ESPCP system configuration is developed. As such, the axial bearing capacity of downhole unit has been effectively improved.

Abstract: For the purpose to clear obverse the impingement and entrainment of the impinging diffusion flame, numbers of the tests are executed under various sets of momentum ratios in this paper. The oxidizer-fuel impinging flames shorten the fully development length. The peak temperature distributions are also greater than that of pure methane impinging flame. Furthermore, its flame width in YZ plane is thicker than that of the pure impinging flame. This effect is more obvious under lean combustion condition. Also, nitrogen gas in the mixture can increase the mixing rate.

Abstract: A shakedown mathematical model of gear contact has been developed. A direct method is applied to solve the mathematical model. Local coordinates are constructed on different meshing points because curvature of gear profile is not constant. Distributions of residual stresses and strains are given base on variable curvature surface. The numerical approach consists of an operator split technique, which transforms the elastic-plastic problem into a purely elastic problem and a residual problem with prescribed eigenstrains. The eigenstrains are determined using an incremental projection method. Contact stresses and contact residual stresses of meshing gear teeth with standard and modified profile are computed. The results show compressive residual stress can improve capacity of gear and operating life. This aspect may contribute to future developments in the understanding of gear durability.

Abstract: Accurate information on heat transfer data of combustion products in the solid rocket motor chamber is a crucial prerequisite for the engine thermal protection. A measurement technique was well developed to acquire steady-state heat flux data of two-phase flow and was used successfully in the hostile environment. Experimental heat flux measurement has been obtained with an innovative designed instrument by simulating the flow field of complex charging configuration. The total heat flux of combustion products in the chamber was brought away by the coolant and calculated by its enthalpy rise in this device. The data could be used to analyze the heat transfer phenomena in SRMs and provide boundary condition for establishing insulation erosion model.

Abstract: To satisfy the requirements of the oil and gas explorations in harsh conditions, an inclinometer based on dynamic tuning gyroscopes was developed. This inclinometer has remarkable temperature and pressure resistance which can be operated under with temperature higher than and pressure greater than . The azimuth angle error is less than and the error of elevation angle is less than . The results of in situ test indicated that this system is can meet the requirements of the oil and gas explorations which needs the azimuth error and slope angle error and is feasible for practical use.

Abstract: In order to study the structure-borne sound radiation, statistical energy analysis (SEA) was adopted and an automobile dash was divided into 31 subsystems; the modal density, damping loss factor (DLF) and coupling loss factor (CLF) were acquired, which were the basic parameters of SEA; then dash transmission loss (TL) at the middle and high frequency (MHF) ranging from 100 Hz to 10k Hz was calculated. The most outstanding advantage of SEA was that calculation could be fast done, which was more convenient than FEM (Finite Element Method) and BEM (Boundary Element Method). Finally, a TL experiment was designed to verify the feasibility and reliability of numerical calculation. The 1/3 octave TL curves of the simulation and experiment show a good consistency and the error is engineering permitted, which means SEA simulation possesses high credibility and can guide the engineering research.

Abstract: At present, our country has stepped up efforts to develop biomass power generation. However, due to the mill not in-depth study of cutting forces and factors in the design of branches crusher which led to the branches crusher can not meet domestic branches of biomass power generation’s demand to raw materials. In the article, the cutting force of the branches grinding has been studied based on BX218 branches crusher. The formula for calculating the cutting force has been deduced. The factors that affect the cutting force have been identified. Finally, ANSYS finite element analysis carried out on the Flying, which is effected by the cutting force.

Abstract: This research paper presents the CFD analysis of oscillating airfoil during pitch cycle. Unsteady subsonic flow is simulated for pitching airfoil at Mach number 0.283 and Reynolds number 3.45 millions. Turbulent effects are also considered for this study by using K-ω SST turbulent model. Two-dimensional unsteady compressible Navier-Stokes code including two-equation turbulence model and PISO pressure velocity coupling is used. Pressure based implicit solver with first order implicit unsteady formulation is used. The simulated pitch cycle results are compared with the available experimental data.

Abstract: Wear of casing string is a common phenomenon in the process of oil and gas exploitation, and it reduces collapse and burst strength of casing string. Stress of internal wall worn casing string must be analyzed to ensure strength of casing string. In the paper, wear form of casing string is assumed as a crescent-shape, and a half finite element model (FEM) of worn casing string, cement-loop and earth combined system is established using the symmetry. Geometry relationships of wear ratio (or wear depth) and the centre of drill pipe are established. Effects of variables such as wear ratio of casing string, magnification factor of wellbore, elastic modulus of cement-loop and working conditions on casing string stress are discussed respectively. Some conclusions are drawn: maximum stress in casing string increases with increased wear ratio of casing string, and ultimately exceeds the yield limit. Increase of magnification factor of wellbore will improve bearing capacity of casing string, but maximum stress in casing string decreases slower and slower with further increase in magnification factor of casing string, at the same time, stress decreases more in casing string than in cement-loop. Minimum stress in cement-loop increases and maximum stress in cement-loop fluctuates with increased elastic modulus of cement-loop, while both minimum and maximum stress in casing string first increases then decreases, the turning point is related to elastic modulus of casing string and earth, as well as the geometry relationships among them. The bigger pressure difference, the larger maximum stress exists in casing string.