Advanced Materials Research Vols. 1006-1007

Abstract: Based on weighted agent sodium chloride, this study introduces a high density and high temperature tolerant fracturing fluid. According to the evaluation of the effect of weighted agent on the performance of base fluid and crosslinked fluid, conclusions can be got as follows. Introduction of weighted agent provides an auxiliary viscosity enhancement of the base fluid to some extent. Meanwhile, the crosslinked time is prolonged and gel breaking becomes more difficult owing to the interference effect of metal ions exerted on the crosslinking process between molecular chains of guar and crosslinker. Moreover, the experiments show that the novel fluid system has a strong tolerance of high temperature and high shearing rate. The viscosity of the fluid system with 15% weighted agent sodium chloride can maintain 160 mPa•s after 120 min shearing at 170 s^-1 under the temperature of 150 °C. The excellent performance of the fluid system ensures it has a good stimulation effect in the fracturing treatment in the deep and high temperature formation stimulation treatment.

Abstract: In the process of thickened oil thermal recovery, the pre-stress cementing needs to be anchored at the bottom of the casing pipe. And the reliable opening and closing of anchor flukes directly influence the anchoring. In allusion to the problems of how to get the critical value of drilling fluid flow rate of when the anchor flukes begin to open, completely open, begin to close and completely close, whether different nozzles can open or close reliably, getting the corresponding differential pressure and discharge coefficient of the different nozzles, this paper conducts a study from both theory and experiment to obtain the relevant parameters. By simulating the anchor in actual work and dealing with the data, we conclude that: (1) The fluke can open smoothly when the flow rate reaches a certain flow and it can also close smoothly when the flow rate declines. (2) The critical flow rate of the flukes, when two kinds of anchors are with different nozzles, has been acquired. (3) Corresponding differential pressure and discharge coefficient of the different nozzles in different flow rate have been ascertained.

Abstract: This article aims to determine roll waves generation criteria for mudflow events. A representative system of equations to mudflows is reached through Cauchy’s equations (mass and momentum conservation) with proper stress tensor (non-Newtonian fluid) in shallow water conditions. Linear stability analysis is then applied to the system and two roll waves generation criteria are found: one related to Froude number and another related to flow disturbance frequency. Numerical simulations for both Newtonian and non-Newtonian fluids were carried. Good agreement was observed between numerical results and theoretical criteria.

Abstract: Using the finite-time thermodynamics, the influence of thermal resistances and nonperfect regenerative losses on the optimal performance of a ferroelectric Ericsson refrigeration-cycle is analyzed. Based on the thermodynamics properties of ferroelectric materials and a linear heat-transfer law, the inherent regenerative losses in the cycle are calculated and the fundamental optimum relations and other relevant performance parameters are determined. The ecological optimization criterion of the refrigerator is derived. The results obtained here may reveal the general characteristics of the ferroelectric Ericsson refrigeration cycle.

Abstract: In order to eliminate the mixed crystals of the thick-walled heavy cylinder after rolling and improve the quench shortage of tank copious cooling, it is significant to analyze the cooling capacity of spray cooling and tank copious cooling. Models of heat transfer coefficient about spray cooling and copious cooling were established. The quenching process simulation was made based on the DEFORM software. The cooling rate models of center part about spray cooling and copious cooling were build. According to the CCT curves of heavy cylinder material and simulation results, which show that: (1) Using spray cooling can increase the cooling rate of center part to some extent and improve the mechanical properties. (2) The maximum capacity of spray cooling is 280mm, that is the microstructure of center part fully transfers to bainite, which is 50mm larger than copious cooling.

Abstract: There is a solution of the problem of stress-strain state determining in a concrete thick-walled tube, when the temperature field and the neutron fluence at the inner face are set. The mutual action of the specified factors is identified in this axisymmetric problem, as well as influence of inhomogeneity of shell materials, which is due to radiation and heat impact. The problem reduces to a differential equation with variable coefficients. The allowance for the mutual action of the specified factors and the variable Young’s module lets to arrive to a more accurate solution.

Abstract: The combustion process of municipal solid waste (MSW) in a operating 750t/d grate furnace in Guangzhou was researched by means of numerical simulation. The influence of MSW moisture content on burning effect was discussed. The results show that: with the moisture content dropped from 50% to 30%, the heat value could be evaluated from 13.72% to 54.91% and the average temperature in the furnace could be promoted 90-248°C. However, the combustible gases and particle in the flue gas of outlet would take up a high proportion since lacking of oxygen would lead to an incomplete combustion. The excess air coefficient should be increased to 2.043~2.593 in order to ensure the flue gas residence time more than 2s and temperature in the furnace higher to 800°C.

Abstract: Combustion characteristics of single base propellant are tested with closed bomb. Combustion characteristic parameters are calculated through P-t curves. Gunpowder force f=974.30J·g^-1, covolume α=1.111cm³·g^-1. Laws of combustion rate are u=4.97×10^-3P^0.82 (charge density Δ₁=0.10g·cm^-3) and u=3.97×10^-3P^0.86(charge density Δ₂=0.16g·cm^-3).

Abstract: Euler-Lagrange method is adopted to simulate 3-D viscous turbulent flow field of a one-stage gas turbine. Gas-solid two-way coupling is realized to analyze the trajectories and slip of 1000 beam particles, with diameter 5~50μm, then calculate the mass erosion rate based on the impact velocity and attack angles. Simulation exhibits: erosion wear is mainly caused by impact of larger particles (>10μm), erosion areas are mainly concentrated on the roots of pressure surface entrance of static blade and on the rear pressure surface of rotor blade. Comparing experiments are conducted between the substrate of X20Cr13 and the specimen with steel-bead injection. Experiment indicates: the attack angle corresponding to the maximal mass loss for substrate is about 40°, while the steal-bead injection is about 50°. Within the scope of the attack angle 20°~80°, the mass loss of the reinforced specimen is obviously less than that of the substrate, and under other angles of attack, the two kinds of material’s erosion tolerance are close to each other.

Abstract: Wave-heated discharges are well known as high-efficiency methods to generate high-density plasma at low pressures. In this paper, three types of plasma sources based on different wave-heated discharge principles are introduced systematically. Electron cyclotron resonance plasma, helicon wave plasma, and surface wave plasma systems are promising to be the next generation of plasma sources to meet increasingly strict requirements in microelectronics industry due to their remarkable advantages over conventional plasma sources.