THE NAVIER-STOKES-CONTINUITY EQUATION SOLVER BASED ON ARTIFICIAL COMPRESSIBILITY METHOD

Fluid dynamics analysis can be accurately approximated by using a computer-based numerical method. Rely on the mass and momentum governing equation, the mathematics model for the compressible condition is numerically difficult to overcome. Through an artificial compressibility method, the quasi-compressible condition solution can be simplified. This study will investigate the classical lid-driven cavity case model to affirm the artificial compressibility method. The result shows that the current model is in-line with the previous study for the lid-driven cavity case. A conventional benchmark with the previous numerical study is shown as well.

Effects of SO42− concentration on corrosion behaviour of carbon steels

Purpose – The purpose of this paper was to investigate the effects of SO42− concentration on the corrosion behaviour of T23 and T12 steels in simulated water chemistry condition solution of 600 MW fossil-fired power boilers. Design/methodology/approach – The influence and mechanism of SO42− ions on the pitting corrosion of T23 and T12 steels in simulated oxygenated treatment water chemistry solution was studied using electrochemical potentiodynamic polarization scans and electrochemical impedance spectroscopy. Findings – The results showed that T23 and T12 were susceptible to pitting corrosion in the simulated solution with full SO42− concentration for the competitive adsorption of OH− and SO42− on the surface of steels. The pitting sensitivity of the steels improved with increasing SO42− concentration. The corrosion resistance for SO42− of T23 was stronger than that for T12. Originality/value – This study is an attempt to provide direction for regulating the concentration of SO42− in boiler water and for selecting the material for boiler water wall tubes.

Effect of Technologies Processing on Material Properties of Selected Aluminium Alloys

The paper is concerned with an analysis of utility properties of selected aluminium alloys, namely EN AW 6082 (AlSi1MgMn), EN AW 6061 (AlMg1SiCu) and EN AW 7075 (AlZn5.5MgCu) with different technology of hot processing. The alloys were hot processed to reach T3 condition (solution annealing, cold forming and natural aging) and to reach T4 condition (solution annealing and natural aging). The following parameters were subject to evaluation: microstructure and sub-structure, mechanical properties (strength and plastic characteristics stated in Table. 1) as well as fatigue properties of these alloys assessed during alternative symmetrical stress in torsion. The paper was aimed to study the affect of processing technology of three aluminium alloys on their utility properties in the conditions of tensile stress and cyclic stress in torsion.

Effect of Heat Treatment and Thermal Exposure on Microstructure of the Alloy C+ Bars

The microstructures of the Alloy C+ with three different heat treatment processes have been investigated after exposure at 550 °C for 100 hours in this study. The alloy shows typical equiaxed β grains with second phase precipitation and twin formation inside the β grains in the as-rolled condition. Solution treatment at lower temperature led to a smaller β grain size while higher temperature solution treatment produced coarse grains with increasing precipitated phases inside the β grains. Ageing treatment after solution and thermal exposure for a long period of time resulted in an increasing α phase precipitation at the grain boundaries due to their tendency for preferential nucleation of second phases. In a certain condition, continuous coarsening of the α phase is concentrated on the grain boundaries therefore violate the properties of the alloy.