Applied Mechanics and Materials Vols. 496-500

Abstract: The design of a vector showerhead in a vertical reactor involves thousands of holes on the showerhead face plate and mass transport in the reactor, and the design variables and objective are always spatial related continuous characteristic, so the discretized sequence of the design variables has too many degrees of freedom that the needed sampling points of a design of experiment or heuristic algorithm methods are hardly acceptable. In order to solve this problem, a profile error feedback (PEF) optimization method was proposed. This method employed a loop-iteration-approximation mode, and started from a guessed initial model, and then fed back the profile error of design objective, according to a weight function, to continually adjusted the design variable sequence to make the gas flow uniformity in the new model continually approximate the perfect one. The optimization case of a vector showerhead system shown that the non-uniformity of the gas flow was reduced from 0.36% to 0.03% under a typical process condition.

Abstract: To meet the requirement of unsteady flow rate generating system for compressible fluid, an inlet flow rate control method with sonic nozzle is proposed. When inlet flow rate is known, feedback of unsteady flow rate can be obtained by an isothermal tank. A proper sonic nozzle is designed according to the technical requirements, and the flow rate is calculated. Open loop experiments are carried out on generating system with and without sonic nozzle. The results indicate that influence of downstream on upstream can be greatly reduced by the designed sonic nozzle, and accurate feedback of unsteady flow rate is ensured.

Abstract: The reliability of the gas turbo-supercharger can be affected by the faults such as the cauterization of the floating bearing of the supercharger, the carbonization of the rotor and getting stuck, the deformation of the blade and heat cracking of the nozzle ring. The design scheme is proposed by using friction bearing taking the place of the floating bearing, because the main reason of the cauterization of the bearing is the increase of the inside clearance of the floating sleeve, which is testified by the actual rpm measurement of the floating sleeve on the floating bearing and the adjustment test of the inside and outside clearances of the bearing. The experimental study on the structural characteristics of turbocharger bearing effectively prevents turbo-supercharger floating bearing from being cauterized, solves the problem of thermal fatigue damage, and improves turbocharger reliability.

Abstract: In order to avoid surge of turbocharger for marine diesel engine, extending service life of turbocharger, we find out some causes and preventive measures of surge of turbocharger for diesel engine due to our accumulation and research in practice. According to the practical test of our company, the causes of surge is accurate and the preventive measures are somewhat productive

Abstract: The distributor is a key component of the gas-solid fluidized bed. It must be guaranteed that the gas has enough stability of pressure drop. In this paper, numerical simulation is used to study characteristics of the distributor pressure drop. The coefficients of viscous loss and inertial loss which describe the porous media model is obtained from the numerical simulation results. Based on the porous media theory, a new simplified equivalent model is proposed, and it can achieve better gas distribution and form uniform pressure chamber. Simulation is also carried out to compare the pressure drop between the distributor model and porous media model. The relative error is only 1.16% in the simulation of this paper, which proves the feasibility of the novel model.

Abstract: According to the present research situation on walking robot, a four-legged walking mechanism based on bionics is presented. The mathematic model of single leg is built in accordance with the projected path. The single leg is divided into driving parts and leg parts. The motion orbits of combined point are optimized using the mathematic model, and the motion character is analyzed according to this mathematical model. The results show the whole mechanism can accomplish the scheduled purpose, the velocity and acceleration of mechanism are reasonable; the trotting pace can also complete the motion simulation. It provides the theoretical basis and reference experience for foot type walking mechanism.

Abstract: The experiments of the fuel economy performance and emission characteristics of diesel engine fueled with butanol diesel were performed on a dual-cylinder direct injection diesel engine at different fuel supply advance angles. The results showed that whether the fuel supply advance angle is too large or too small, it will increase the fuel consumption. As the fuel supply advance angle is 20°CA, the brake specific fuel consumption is the best of the butanol diesel engine. When the supply advance angle becomes larger, the smoke and CO emissions can be reduced on the medium and high loads, but NO_X emissions are significantly increased on a variety of load conditions. The engine will obtain the lowest HC emissions, as the fuel supply advance angle is 20°CA.

Abstract: The main content of this paper is to design and fabricate a type of surveillance ship with a proton exchange membrane fuel cell (PEMFC), which adopts hydrogen as fuel cell to generate electricity to drive the surveillance ship. This ship has devices of reconnaissance, lighting, shooting. The reconnaissance device could return real-time images to the command center via cloud technique which could understand the current situation of the reconnaissance location. A buoyancy device is designed into the hull to enhance the stability of running. This paper starts from the functional design and system evaluation, then conducts the fabrication and assembly of the surveillance ship, and finally makes the electric integration and the tests of the PEMFC, surveillance ship running, and hydrogen consumption. The results of the research shows the developed surveillance ship has the advantages of low pollution, clean energy, no effect of day and night, and could be driven via only a small amount of hydrogen, which meets the trend of environmental protection and has the potential of applications in the future.

Abstract: in order to change China's shipbuilding capacity continues to rise, while the ship equipment localization rate decreased and the situation of reality , the national defense science and Industry Committee put forward the strategic planning of shipbuilding, coordinated development. Marine auxiliary is the largest number, the most species of ship equipment. Based on the analysis of structural weaknesses of the previous ship swash plate axial piston pump, designed a kind of improved fixed swash plate axial piston pump

Abstract: Transformation from bullet to aircraft is the key technology for parachute aircraft. The transformation occurs at the end of initial bullet trajectory, so the simulation of trajectory can help us to analysis the affect factors. Contrast with tradition trajectory, the initial trajectory of parachute aircraft contains three phases: launch inside trajectory, free-control trajectory and parachuting trajectory. This work adds parachuting model into tradition trajectory model, and built simulation model on computer. Furthermore, to confirm the effect from parachute area and time of unfolding parachute, analysis for falling speed and time of stability (attack angle and roll) are made, and then the relates among these factors are summarized.