Papers by Keyword: Experiment

Abstract: This paper deals with a problem of eigenfrequencies of cylindrical tank (steel water tank). For an ANSYS analysis of eigenfrequencies some numerical models of cylindrical tank are used and finally results got by these models are compared with experimental results in laboratory. In final part of the paper some crucial results are presented both in a graphical and numerical way.

Abstract: This paper introduces a new type of solar water heater——Parabolic trough solar water heater,the biggest feature of the solar water heater is that the parabolic trough reflector can reflect light onto the tube with reflective principles,which may lead to lots of advantages,such as more strong solar energy flux density,fewer losses,fewer tubes used.In a word,the cost is reduced while the performance is guaranteed.On this basis,we built a collector area of about 1.54 square meters of parabolic trough solar water heaters bench and made experiments to test.Instantaneous average efficiency and daily average efficiency of the water heater can be calculated.Efficiency curve can also be generated.Meanwhile we measured the heat loss coefficient of the water heater.The results showed that the daily average efficiency of the parabolic trough concentrating solar collector is between 30% and 50%,while at higher temperatures the collector showed its good insulation properties.

Abstract: A multi-point low-pressure methanol injection system was installed on manifold of a four cylinder turbocharged diesel engine, and the experiments on the engine operated with intake premixed methanol were conducted under wide operating conditions. The influence of the engine operating conditions on premixed methanol quantity was analyzed. The results show that, compared with straight diesel model, premixed methanol prolongs the ignition delay time of pilot diesel at the engine high load with low speed, and more methanol quantity can be premixed. At more than medium load with high speed, diesel ignition delay time with premixed methanol is shorter than with straight diesel model, and substitution ratio of methanol for diesel is significantly lower than that of low speed. Compared with the straight diesel mode at high speed, the fuel economy of the dual fueling mode is better, and NOx and soot emissions also are decreased, but CO and HC emissions are increased.

Abstract: In acid fracturing, the fast acid-rock reaction limits live acid penetration distance. Many kinds of acids were developed to reduce the acid-rock reaction rate. Acid effective consumption time in the fracure is a key factor for accurate prediction of live acid penetraiton distance in acid fracturing designs. In this paper, we developed a new method for measuring acid effective consumption time in the fracture and did experimental result matching to obtain effective acid diffusion coefficient with a acid flow-reaction model. Firstly, we designed a apparatus and corresponding experimental procedure. Then used the new method to measure the effective consumption time for gel acid and crosslinked acid. The new method uses reservoir core samples and is convenient to heat all the fluid as well as pipe lines to the reservoir tempeature, which reflects in-situ conditions more reliably. In the experiment, the rock mass loss with time was measured, based on which the acid consumption time is predicted. Under the experiment conditoins, the gel acid has a effecive consumption time about 17-minute, and the crosslinked acid has about 22-minutes at 130°. Finally, a model of acid flow-reaction in a fracture was used to match experimental results to obtained the acid diffution coeffecient. The results from this study help improve accuracy in acid fracturing designs.

Abstract: Influence of relative clearance to hole quality is investigated by numerical simulation and experiment. The numerical simulation in punching process of sheet metal is conducted by using ANSYS/LS-DYNA.The relative clearances in two sizes are selected to investigate the difference of holes cross section. Influence regularity of the relative clearance to hole quality is obtained by experimental investigation.

Abstract: This paper introduced a kind of fast tool servo (FTS). Base on in the frame rack, flexible hinge, piezoelectric ceramic driver, tool base, diamond tools and so on. Laser interferometer is used for displacement measuring of the fast tool servo. The structure simulation was done to the FTS and the nature frequency was obtained. The output displacement of FTS was measured by Laser interferometer. Four kinds of different sin wave sign were given and the frequency of driving voltage ranged from 10Hz to 400 Hz. The relation of the displacement and the driving voltage frequency and the relation of displacement and the driving voltage had been established by experiment.

Abstract: This paper will introduce the general situation of railway communication, expound the necessity of railway GSM-R communication experiment platform construction, analyze the significance and role of practice teaching, especially the content of construction and project are described.

Abstract: In order to generate low frequency acoustic wave and minish the ratio of the length to diameter, it is appropriate to instead the circular jet by annular jet as the high pressure gas power. So the larger diameter of jet and resonator are got in the condition of the same pressure and flux. Flow simulations and experiments have been performed in order to better understand the behavior of the powered resonance tube (PRT) driven by annular. Simulation and experiment results show the PRT can be excited by a annular jet, and produce low frequency high-amplitude dynamic pressures and acoustic emission. The compression wave and expansion wave transmit into and out of the resonance tube alternately in a cycle and a cycle can be decomposed to two distinct stages of filling and evacuation. In experiment PRT can work in the low frequency at very low pressure, and PRT can generate intense sound wave at frequency from 50~3200Hz.

Abstract: In order to solve the contradiction between the increasing demand of power supplies and the difficulty of building new distribution lines, improving the transmission capacity of existing distribution cables is imperative. Using emergency ampacity can increase cable transmission capacity temporarily. Software of calculation emergency ampacity of distribution cable is developed and experiments are undertaken in this paper. The consistency of calculation and experiments shows that the software could calculate emergency ampacity of distribution cable correctly. By the software, the relationship between emergency ampacity and emergency time & initial status are studied here. The research shows that emergency ampacity is much higher than the continuous ampacity. What’s more, the shorter emergency time is, the higher emergency ampacity will be. The lower initial current is, the higher emergency ampacity will be. The more cable circuit number is, the lower emergency ampacity will be but the stronger lifting capacity will be. If emergency ampacity is considered in cable line design stage, cable cross-section or the number of circuit number could be reduced; and if emergency ampacity is considered in emergency load control, the number and capacity of transferring power supply can be reduced. The application the emergency ampacity of distribution cable will result in a great improvement in economy and reliability of power supply.

Abstract: Reasonable matching with each accessories’ mechanical adaptability of anchor bolting system is the basis for the protection of support effect in roadways. In this paper, taking Huozhou mine area for example, load process of four kind of bolt bars with different spec, bearing capacity of circular pallets, and transformation test of bolts pretension moment were compared and analyzed by loading method in laboratory. The results show that, pallet arch structure significantly impact on its bearing capacity. the two kind spec of circular pallets’ bearing capacity were not sufficient to match tensile force requirements of the high strength bolt, the pallet arch height needs to increase to meet the high load demand. Various anti-friction components significantly improve pretension transformation for bolt moment, in which, nylon gasket can increase the conversion efficiency with more than 30%, and the steel ball bearing with one multiple nearly.