Abstract: In this study, computational simulations were made using ANSYS CFX to predict the improvements in film cooling performance with multi trench. Multi-trench configuration consists of two trenches together, one wider trench and the other is narrow trench that extruded from the wider one. Several blowing ratios in the range (0.5, 1, 2 and 3) were investigated. By using the multi trench configuration, the coolant jet impacted the trench wall two times allowing increasing the spreading of coolant laterally in the trench, reducing jet velocity and jet completely covered on the surface. The results indicate that this configuration increased adiabatic effectiveness as blowing ratio increased. The multi trench configuration increased adiabatic effectiveness up to 100% near the hole, 43% at X/D = 40 and 31% at downstream X/D = 137 for blowing ratio of 3 and no observed film blow-off at this blowing ratio. The adiabatic film effectiveness of multi trench configuration outperformed the narrow trench at different blowing ratios
Abstract: Energy conservation and environmental protection is the two themes of the maritime transport development, through discussing the necessity of the incinerator waste heat utilization. Analysis the feasibility of incinerator waste heat using on ship air conditioning ,and puts forward specific technical plan to absorption refrigeration and air conditioning equipment using Marine incineration waste heat.
Abstract: Through the analysis of the basic principles of vibration drilling and vibration drilling process, in the drilling device and the cutting parameter sides , combined with the actual structure of the workpiece as well as the ultrasonic vibration drilling processing methods to elaborate, using the ultrasonic vibration drilling device to carry out the TC4 titanium alloy micro-hole drilling test. The test prove that selecting reasonable cutting parameters can solve the problem of drillingTC4 titanium alloy micro-hole that size is Φ1.5mm × 12mm , fully reflects the superiority of the ultrasonic vibration drilling. A new method was afforded for titanium alloy micro-hole drilling.
Abstract: In order to quickly determine the weak links of micro-accelerometer in vibration environment, the test profile of step stress and sustained stress were designed in the vibration environment on micro-accelerometer, the relevant reliability enhancement test was actualized for micro-accelerometer of 10g, the failure time was given in the sustained stress. The failure mode and failure mechanism were analyzed by detailed test results, the ANSYS software was used to simulate the move route and stress distribution of cantilever beam in the conditions of being adhesion strength and without it. According to the step stress test and constant stress test of RET, the various stress limit, the relevant failure mode and the failure mechanism were given in the vibration environment.
Abstract: Analyzes that the ammonia plant of a fertilizer between rich liquid line and ammonia synthesis tower of pressure pipeline vibrates some reasons, through the establishment of the pipeline and tower body vibration finite element model, the calculation of the existing constraints stress, vibration frequency and vibration form. By adding a support level and put forward the reconstruction plan of vibration reduction. Through many calculation and analysis, the weld seams stress reduced by 23.6%, the maximum amplitude dropped 98.5% and obtain the better vibration reduction transformation effect.
Abstract: Shaking table test is an important method to study on the problem of the soil-structure dynamic interaction. The property of the soil container directly affects the accuracy of the result. A laminar shear container was designed for shaking table test. And a shaking table test on soil-underground structure dynamic interaction which structure lay in clay was conducted. The results of the test show that the container eliminated the boundary effect when the dynamic load was applied in only one horizontal direction. Meanwhile, the stiffness of the soil container could be changed according to the change of the model soil, which is applicable to decrease the boundary effect.
Abstract: Based on the taking sample by geological drilling, combined with the fractal principle, analysis on the cracked backfill particle size of its fractal features and strength correlation. Even each backfill sand specimen particle size is difference, but calculation data shows that the particle size of each sand specimen has preferable fractal feature, the sand specimen particle size distribution has remarkable fractal structure by the linear fitted results of the sand specimens. The fractal relationship of strength and particle size distribution shows that with the increased of fractal dimension, the strength of backfill is decreased, that is to say there is negative correlation, the main cause is that the higher parameter D of the fractal dimension, the higher fine-grained content and more non-uniform of the particle size distribution, especially for the thinner full tailings, if properly increasing the content of slightly crude particles, the strength of backfill will be certainly improved to some extent.
Abstract: In order to find the reason why a rare distant-earthquakes abnormal high intensity occurred in Hanyuan county town during 2008 Wenchuan Earthquake of China, the earthquake damage was studied from resonance effect point of view. The seismic records of Wenchuan Earthquake in Hanyuan were collected, and their dominant periods were obtained from their Fourier spectra. Based on transfer function of 3 engineering geological boreholes surveyed in Hanyuan county town, the fundamental period of the sites the was calculated. The natural vibration periods of the structures there were estimated by the empirical formulas of natural period according to their structure type. It was found that the tree periods were close very much, and the resonance was prone to occur. The resonance effect was one of the main reasons which caused abnormal high intensity in Hanyuan county town.
Abstract: In order to reveal the deformation and failure mechanism of coals, the evolution of coal’s inner structures should be discovered and studied. A serial of coal specimen collected from 600m deep underground mine were scanned by a μCT system before and after conventional triaxial compression testing respectively. All the CT images were enhanced by some digital image processing techniques and then collected together to reconstructed 3D models by self-developed software. The stress-strain curves of coals at different confining pressure were obtained, and correspondingly the evolution of the inner structure of coals were well presented by enhanced CT images. Experimental results indicate that the strength of coal agrees well to linear Mohr-Coulomb Criterion. CT images show that more cracks occurs with the increasing confining pressure. It was inferred that the damage become more severe with increasing confining pressure and cause the variation of failure from ductile style at low confining pressure to brittle style at high confining pressure.
Abstract: Soil classification results from CPT/CPTU always involve the uncertainty of correlation between mechanical behavior and soil composition. For better processing large quantities of tests data obtained form CPT/CPTU, Modified Bayesian model was introduced and corresponding soil classification method was proposed. The validity of the new method was verified through local silt samples. Evaluation results also suggested that the proposed new soil classification method had well applicability.