Advanced Materials Research Vols. 694-697

Abstract: Based on the Reynolds equation considering the temperature, the effection of non-newtonian and the magnetic field, the elastohydrodynamic lubrication(EHL) analysis of water-based ferrofluid journal bearing were carried out. The influence of roughness peak height and wavelength on the journal bearing surface with cosine roughness model were analysed. The results reveal that the pressure and film thickness of water-based ferrofluid wave apparently with roughness fluctuation; The fluctuation range of pressure and film thickness increase with the increase of roughness peak height, the minimal film thickness decreases; The pressure and film thickness fluctuation range become more and more sparse with the increase of roughness wavelength, the minimal film thickness increases.

Abstract: The objective of the present work is to characterize and investigate the effect of aspect ratio and twist angle of elements on the pressure drop predictions in Kenics static mixers using three-dimensional CFD approach. Twenty different kinds of Kenics mixers have been characterized. The numerical approach took into account the relationship between pressure drop and aspect ratio and relationship between pressure drop and twist angle at high Reynolds number within the Kenics mixer, which was neglected in previous studies. It is found from the study that the pressure drop is the function of aspect ratio and twist angle with a specified geometry at a certain flow rate.

Abstract: It is hard to accurately predict the shape and the characteristic of jet because of the dynamic characteristic of water jet in the atmosphere. The Eulerian model was used to calculate the water jet numerical simulation of two-phase flow. The distribution of the velocity, pressure and the component of the nozzle flow field were obtained under the condition of the initial pressure of nozzle is 100 MPa and the outlet diameter of nozzle is 0.2 mm. The results show that fluid velocity increases rapidly in the nozzle contraction section and appears the isokinetic core area after leaving the nozzle; the fluid dynamic pressure rapid rises in the nozzle contraction section and keeps invariant at the isokinetic core area; the ratio of the contraction flow radius and the nozzle radius is 7:10.

Abstract: Through the numerical simulation method, the Reynolds stress turbulence model (RSM) was used to simulate the flow field of circumfluent cyclone separator with three different outer chamber heights. Three circumfluent cyclones (CFC), with different outer chamber heights, are compared with each other. Pressure fields, velocity fields and pressure drop have been investigated. The results show that in a certain range, the outer chamber height of circumfluent cyclone separator has an optimum value, which can have higher separate efficiency and lower pressure drop. This provides a strong theoretical basis for the local optimization design of the cyclone.

Abstract: Wave machine is one of the necessary laboratory equipments to optimize the structures and devices in the field of marine engineering. For the purpose of putting forward a new hydraulic servo wobble board wave machine system, we designed the mechanical structure, and carried out the mathematical model of the servo system. The MATLAB analysis result showed that the wave machine was reliable. This research therefore provided fundamental experience for the manufacture of the wave machines and the marine engineering laboratory equipments, and also worked as a reference for the establishment of the other hydraulic servo systems.

Abstract: The formulae of resistance loss for combined and divided flow through T-type equal diameter duct and correlations between resistance loss coefficient in each branches were derived from energy method, on this basis, the numerical simulation studies on resistant characteristics of laminar oil in T-type equal diameter duct with different flow model applying for hydraulic pipeline were conducted by using CFD method, and the reasons induced resistance loss were analysed base on the pressure change mechanism in the flow field, additionally, the numerical results indicate that the resistance loss of hydraulic oil through T-type duct relations with magnitude and matching direction of the flow speed in each branches, and can be applied to optimize the design of hydraulic pipeline, and reduce energy loss.

Abstract: The development of hydraulic free piston engine (HFPE) in China is still in the beginning stage of exploration. Based on the project of research group, the coolant flow and heat transfer of water jacket’s for the HFPE were simulated with the three-dimensional CFD software FLUENT, and the field information of the velocity field, pressure field and the transfer coefficient of coolant in the water jacket were achieved. The results indicate that the requirement of cooling system can be meet except some small problems, but it provides a reference for the engine design in the future.

Abstract: The hybrid-driven underwater glider (HUG) is a new kind of underwater vehicle; it combines the best features of autonomous underwater vehicles and underwater gliders, and can be used as important platforms for marine environment observation and ocean resource exploration. It’s difficult to get the drag coefficient of HUG through theoretical formula. In this paper, we use analysis software Fluent to analyze the HUG with different attack-angle and velocities, get the lift 、 drag coefficient and lift-drag ratio, and determine the biggest lift-drag ratio of HUG in the attack- angle of 6 degrees.

Abstract: The performance of one-way inlet valve directly impacts the effect of the reflux scavenging two-stroke engine intake. It’s discovered that the intake air flow rate, the weight of valve and the spring constant have the greatest impact on the opening, closing and the lift change of one-way inlet valve, by simulating the movement of piston and valve using CFD software. The greater the flow rate, the smaller the weight of valve, or the smaller the spring constant, then the faster the opening of valve. Meanwhile, in order to ensure that the valve quickly returns, the bigger of spring constant is the better. The phases of opening and closing of valve lag fall behind the phases of piston getting to bottom dead center (BDC) and top dead center (TDC).

Abstract: The paper presents a new type of machine that can be used as well as working machine or as force machine. The machine consists of two purpose-machined rotors that rotate with the same speed inside a casing; relations used for the computation of machine flow rate and power are presented, as well as results of experimental researches performed for an experimental model tested on a setup.