Papers by Keyword: Jet

Abstract: During the test of DC(direct current) abrasive magnetic fluid technology,many bubbles and noises were generated near the graphite electrode , and the yellow green liquid was produced, which affected the further test.Through the study of graphite electrode, it was found that NaCl solution magnetic fluid produced hydrogen and chlorine gas after electrolysis. At the same time, chlorine gas dissolved in water to form yellow green liquid.The magnetic field of neodymium boron permanent magnet was equivalent to a mechanical stirring, which inhibited the production of chlorine gas.According to the difference of impressed current system, the abrasive magnetic fluid jet technology was divided into DC and AC(alternating current) .There was no electrode in AC abrasive magnetic fluid jet technology, so no gas or noise would be produced.The rotating magic ring permanent magnet produced alternating magnetic field, acting on the abrasive magnetic fluid to form an induced current.Under the action of the magnetic field, the electromagnetic force was applied to move along the circumferential direction to promote the motion of the abrasive magnetic fluid.

Abstract: There are massive reports about near-field electrospinning (NFES) in the literature and the NFES has great tendency for scientific and industrial applications. It is important to improve the machining efficiency of electrospinning. Through the study of the multi-nozzle near-field electrospinning, a new method by adjusting the electrode-to-collector distance (E-C-D) is presented in this paper to make sure the jets with a straight line. The method is divided into two steps: (1) to adjust the E-C-D larger to get the jet at each nozzle, (2) to make the E-C-D smaller enough to get straight jets. Moreover, this paper simulates the electric field density which helps to provide a further understanding on the process of NFES. The experimental results contribute to making a better control on the jets in NFES.

Abstract: The earthworm is a common terrestrial animal, its physical structure and morphology characteristics are very distinctive. Through of imitation of the special abilities of earthworms, people can get the material to research on bionic technology, such as the jet, non-smooth surface, etc. It can provide the new design ideas for engineering technology. The study of earthworm body structure and its movement mechanism, can help people to find the drag reduction method in the process of movement. In addition, the earthworm non-smooth body surface, dorsal pore jet, surface lubrication, electroosmosis and its unique moving way form a good drag reduction effect. Therefore, research on earthworm is instructive for the development of bionic technology.

Abstract: The mixing characteristics of a sonic jet issuing from a circular orifice and nozzle of same exit area, controlled by U-shaped tabs were studied experimentally, in the presence of a favorable pressure gradients corresponding to nozzle pressure ratios (NPRs) of 3, 4 and 5. Mixing of controlled and uncontrolled jets from orifice and nozzle, with the surrounding environment has been analyzed, using the jet centerline pressure distribution. The waves prevailing in the jet field were visualized using shadowgraph technique.

Abstract: Multiple schemes are adapted on truck's outer flow field based on numerical simulation. Comparative analysis with the state of air flow, the pressure distribution, the air movement between the cab and cargo is pursued, then obtain the effect of jet flow velocity to the truck Cd. With the increasing of the jet velocity, Cd increases first and then decreases. The maximum drag reduction can reaches 7.38%.

Abstract: A variable density anisotropic turbulent buoyant jet model is applied for simulating the current field under waves. The numerical simulation results show the present model is efficient to describe the construction characteristic of current field. This model could be an efficient tool for sewage treatment by deep sea discharge.

Abstract: Deriving inspiration from the propulsion methods of squids, a pulsatile jet propulsion system is adopted in a robotic model. A squid-like direction control mechanism, which can direct the jet along any direction on a hemispherical work volume, is also implemented. To obtain a suitable robot velocity (_v) and a propulsive efficiency (η_p) for testing this mechanism, the stroke ratio (L/D) and outlet diameter are varied and the _v and the η_p of various alternatives are estimated experimentally using vision analysis. A Stroke ratio of 3.78 and an outlet diameter of 25.4 mm were found suitable and employed for testing the mechanism. When the jet is deflected by 60° in the horizontal plane, the robot rotates about its centroid, signifying excellent maneuverability. Reverse motion was also demonstrated by removing inlet valves and blocking the outlet through the direction control mechanism. The performance of the direction control mechanism indicates that the robotic model was a feasible alternative to conventional screw-propelled aquatic robots.

Abstract: Efforts have been given to improve the turbine blades ability to withstand high temperature for a long period of time by implementing effective cooling system. There are many aspects that should be considered when implementing impingement cooling. This paper will only cover two trending aspects in impingement cooling implementation; the jet-to-target plate distance and the application of ribs in promoting better impingement cooling performance. For target plate distance to impingement jet diameter value, H/d > 1, the area-averaged Nusselt number also decreases as the H/d value increases. This may have been due to a reduction of the amount of momentum exerted by the impinging jets onto the target plate. For H/d < 1, the results have been proven otherwise. Heat transfer in impingement/effusion cooling system in crossflow with rib turbulators showed higher heat transfer rate than that of a surface without ribs because the ribs prevent the wall jets from being swept away by the crossflow and increase local turbulence of the flow near the surface. It could be concluded that both H/d ratio and ribs installation play an important role in enhancing impingement cooling systems heat transfer effectiveness.

Abstract: The new fluidization method of liquid-liquid circulating fluidized bed proposed for ice slurry production was investigated experimentally. Multiple small water-drops were formed in another immiscible liquid coolant by a single-nozzle atomizer and frozen in the fluidized bed by direct contact heat transfer. Experiments were conducted to research the dynamic behaviors of jet and drops formation in the ice making system by the high resolution digital camera and image processing. The photos of jet development, breakup and drop formation were obtained. The affects of the shape of jet breakup, jet length and its surface fluctuation on drops size were revealed. The range of drop sizes and the sloping extent have always increased with the jet rate increasing. And varying jet shape directly results in the jet breakup into droplets under different time and test conditions, so the variation laws of the jet shape contribute most to the quality of the liquid drop, such as drop size distribution.

Abstract: Layered carbon fiber composite performing microstructure was a part of multi-layer porous piping dielectric structure. At first a jet mechanism was put forward and researched for layered composite materials. The Z reinforcing fibers puncture was put to the layered composite structures. By the CFD simulation analysis, the feasibility of jet puncture was verified, the interlayer strength of the connection was increased and the Z bunch to the carbon fiber was eliminated, which laid theoretical foundation by enhancing the layered carbon fiber composite perform quality.