饮水机水嘴注射模的设计

通过对饮水机水嘴的工艺分析,设计了一模两腔的注射模。在模具中设计了圆锥螺纹脱模机构、液压侧抽芯机构、浇注系统和其它结构的设计,以及模具工作过程。

火焰清理机烧嘴浮动对板坯清理质量的影响

应用计算流体力学方法模拟不同浮动量下的烧嘴预热清理火焰状态,分析不同浮动量的烧嘴火焰形成机理,进而研究火焰清理机浮动量对板坯清理质量的影响。

砖瓦挤出机成型装置的设计

本文阐述了当前国内砖瓦挤出设备存在的问题，分析了砖瓦挤出机机头和机嘴部分参数对挤出成型的影响。

硫磺尖嘴式滴落成型工艺的扩能措施

本文简要介绍硫磺尖嘴式滴落成型工艺的工艺原理,并结合实际生产案例,阐述了该硫磺成型装置尖嘴式滴落成型机的扩能改造措施以及产品成型质量的调整方法,实现了硫磺成型装置的产能提升,使装置满足生产需求并保持长周期安全平稳运行,同时,保持较好的产品成型质量,对同类型硫磺成型装置的产能提升及产品成型质量调整具有一定借鉴作用。

Experimental Investigation on Mixing Enhancement Mechanism of Turbulent Jet Flow with Tabbed Nozzle

Flow visualization and hot-wire measurement techniques were combined to investigate the influence of the size and number of tabs on jet flow field and vortex structure generation mechanism. Streamwise vortices generated by the tabs of different sizes and numbers were observed from the flow visualization images. Combined with flow visualization, hot-wire measurement gave a quantitative insight of the effect of various tabbed jet flows. Instantaneous two-component velocity signals (longitudinal and transverse velocity components) at different cross sections along radius direction and streamwise direction with different tabbed jet nozzles were measured using hot-wire anemometer. Average flow field parameters of tabbed jet flow such as mean velocity, tur-bulence intensity, vorticity were analyzed and the effects of tabs with different sizes and numbers were compared with that of circular no-tab jet flow. It is revealed that the generation of a series of counter-rotating quasi-streamwise vortices, azimuthal vortices and double-row azi-muthal vortex are the reasons for mixing enhancement of tabbed turbulent jet flow.

Influence of Diesel Nozzle Geometry on Cavitation Using Eulerian Multi-Fluid Method

Dependent on automatically generated unstructured grids, a comprehensive computational fluid dynamics(CFD)numerical simulation is performed to analyze the influence of nozzle geometry on the internal flow characteristics of a multi-hole diesel injector with the multi-phase flow model based on Eulerian multi-fluid method.The diesel components in nozzle are considered as two continuous phases, diesel liquid and diesel vapor respectively.Considering that both of them are fully coupled and interpenetrated, sepa...

Middle or low water pressure direct spiral double helix converging nozzle structure optimization and flow field analysis

In order to solve the problem of using new nozzle is proposed in fire rescue robot. middle or low water pressure to form fine water mist, a Existing water mist nozzles are basically used for high pressure and in large size, complex structure and poor low pressure atomization effect in comparison with requirement of snake-like fire rescue robots. On the basis of comprehensive typical spray noz- zles, a direct spiral double helix converging nozzle （DSDHCN） is proposed, which has the advanta- ges of small volume, light weight, simple structure, and convenient installation. To make the spray nozzle have good performance, and meet the requirements of more efficient fire extinguishing, a nu- merical study is carried out to analyze the internal and external full flow field of nozzle. A gas-liquid two-phase flow is applied to simulate the external full flow field of nozzle with VOF model in fluent software. The simulation results show the real situation of water flow out of the atomization nozzle and the water jet trajectory. Some simulations about middle or low water pressure direct spiral double he- lix converging optimized nozzle have been done in 30bar pressure. The simulation results show that the optimized nozzle structure not only makes the spray droplets have a good cone angle, but also have a sufficient axial velocity,which proves the structure rationality of the proposed optimized nozzle.

鸡用切嘴机的使用注意事项

1.接通电源后,将调温旋钮转到最大位置,使刀片呈红热状态,再根据鸡龄调节调温旋钮,使刀片呈微红或暗红.

Failure in Fuel Injector Nozzles Used in Diesel Engines

This paper aims to conduct a study of the problems associated with the wear of the needles and fuel injection nozzles utilized in diesel engines. The wear found on the needles is mainly associated to impurities in the fuel oil and microcavitation occurred due to high pressure in the phase of the air compression for combustion of the combustible fluid. These pressures associated with the temperature and the fluid velocity results in the occurrence of vaporization, which releases shock waves that cause damage to the affected surface. The impurities solid particles from the fuel oil cause problems inside the nozzles as obstruction of the holes and wear on the needle tip and nozzle seat surface. These failures affect in the atomization of the fuel, since the deterioration of the internal passages of the nozzles interferes in the spray formation and in the end passage of the fluid. For the execution of this study it will be used digital microscopic analysis in specimens that suffered damage, in order to investigate the effects of fuel property, and the temperature conditions and pressure in the formation of the wear on the needles and injector nozzle.

Air Velocity Fluctuation in Reed Groove of Air-Jet Loom

The airflow in the reed groove of the air jet loom for the weft insertion includes the jet stream from the relay nozzle, the back leak stream from the reed, and the diffusion stream from the open side. The air velocity in the reed groove can be measured to analyze the influence of process parameters during the weft insertion. The relation between the air velocity and the relay nozzle distance, the jet angle or the supply pressure of the relay nozzle can be studied. In this paper, the pitot tube is applied to measure the air velocity in reed groove by the instrument designed. And the results indicate that the air velocity fluctuation in the reed groove is strong, and can drop from 150 m·s-1 to 80 m·s-1 drastically.

Cooling of the Vulcain Nozzle＇s Divergent Wall

Rocket engine nozzle is a propelling nozzle used to expand and accelerate the combustion gases produced by burning propellants to supersonic exit velocities. To furnish high performance and thrust, a maximum of the energy which is released inside the combustion chamber due to the reaction of the propellant and the oxidizer has to be converted into kinetic energy. This converted energy emits high heat fluxes that damage the nozzle that is so expansive to realize. For this matter, lots of researches were established to invent multiple cooling techniques in a way to avoid the damage of the nozzle, so recovering it for to be operative again. This work aims to identify the quality of cooling using the method of film injection. A numerical simulation is run on a scale model of a BKE propulsive nozzle. A parietal injection is conducted in the divergent section where the heat fluxes are enormous what allows us to predict the static temperature ＆ pressure on the walls without parietal injection ＆ then we include it in the parameters in order to see the efficiency of the film cooling technique in the nozzles. For this study, we used two different calculation codes： Ansys-Fluent was used to realize the simulation of the supersonic flow ＆ the parietal injection, where Solidworks simulation was used in the thermal study. The effects of the thermal fluxes ＆ pressure after ＆ before the fluidic injection on the wall are discussed.

Nozzle Light Powered by Energy Harvesting Technology

The invention of this study harvests a portion of hydropower in the fire hose to drive a micro turbine generator and the electric power generated is used to light the LED （light-emitting diode） attached on the fire nozzle for the illumination of dark scene （it is called nozzle light in this study）. The simulation and experiment are done to match the design of nozzle light. Nozzle light provides firefighters a synergistic function to spray the water and illuminate the fire field at the same time without requiring any extra hand to handle the light. It indeed increases both the efficiency of putting off a fire and the safety of firefighters. The most innovative benefit is that neither heavy battery nor utility wires are needed to get the lighting.

Comparisons of nozzle orifice processing methods using synchrotron X-ray micro-tomography

Based on the high flux synchrotron X-ray of the Shanghai Synchrotron Radiation Facility (SSRF), high precision 3D digital models of diesel nozzle tips have been established by X-ray micro-tomography technology, which reveal the internal surfaces and structures of orifices. To analyze the machining precision and characteristics of orifice processing methods, an ap- proach is presented based on the parameters of the internal structures of nozzle orifices, including the nozzle diameter, the orifice inner surface waviness, the eccentricity distance and the angle between orifices. Using this approach, two kinds of nozzle orifice processing methods, computerized numerical control drilling and electric discharge machining, have been studied and compared. The results show that this approach enables a simple, direct, and comprehensive contrastive analysis of nozzle orifice processing methods. When processing a single orifice, the electric discharge machining method has obvious advantages. However, when there are multiple orifices, the error levels of the two methods are similar in relation to the symmetry of distribution of the orifices.

Numerical Analysis of Shock Induced Separation Delay by Air Humidity

In this paper numerical calculations of the dry and humid air flows in the nozzle are presented. The dry air flow (adiabatic flow) and the humid air flow (flow with homogeneous condensation, diabatic flow) are modeled with the use of Reynolds Averaged Navier-Stokes (RANS) equations. The comparison of these two types of flow is carried out. The influence of the air humidity on the shock wave location and its interaction with the boundary layer is examined. Obtained numerical results present a first numerical approach of the condensation and evaporation process in transonic flow of humid air. The phenomena considered here are very complex and complicated and need further in-depth numerical analysis.

Numerical Investigation of the Effects of ITD Length on Low Pressure Nozzle

The advantage of high efficiency, low SFC(Specific Fuel Consumption), ultra-high bypass ratio turbofan engine attracts more and more attention in modern commercial engine. The intermediate turbine duct(ITD), which connects high pressure turbine(HPT) with low pressure turbine(LPT), has a critical impact on the overall performance of turbine by guiding flow coming from HPT to LPT without too much loss. Therefore, it becomes more and more urgent to master the technique of designing aggressive, even super-aggressive ITD. Much more concerns have been concentrated on the duct. However, in order to further improve turbine, LPT nozzle is arranged into ITD to shorten low pressure axle. With such design concept, it is obvious that LPT nozzle flow field is easily influenced by upstream duct structure, but receives much less interests on the contrary. In this paper, numerical method is used to investigate the effects of length of ITD with upstream swirl blades on LPT nozzle. Nine models with the same swirl and nozzle blades, while the length of ITD is the only parameter to be changed, will be discussed. Finally, several conclusions and advices for designers are summarized. After changing axial length of ducts, inlet and outlet flow field of nozzle differs, correspondingly. On the other hand, the shearing stress on nozzle blade(suction and pressure) surface presents individual feature under various inlet flow. In addition to that, "Clocking-like effect" is described in this paper, which will contribute much to the pressure loss and should be paid enough attention.

Effects of Nozzle-Strut Integrated Design Concepton on the Subsonic Turbine Stage Flowfield

In order to shorten aero-engine axial length,substituting the traditional long chord thick strut design accompanied with the traditional low pressure(LP) stage nozzle,LP turbine is integrated with intermediate turbine duct(ITD).In the current paper,five vanes of the first stage LP turbine nozzle is replaced with loaded struts for supporting the engine shaft,and providing oil pipes circumferentially which fulfilled the areo-engine structure requirement.However,their bulky geometric size represents a more effective obstacle to flow from high pressure(HP) turbine rotor.These five struts give obvious influence for not only the LP turbine nozzle but also the flowfield within the ITD,and hence cause higher loss.Numerical investigation has been undertaken to observe the influence of the Nozzle-Strut integrated design concept on the flowfield within the ITD and the nearby nozzle blades.According to the computational results,three main conclusions are finally obtained.Firstly,a noticeable low speed area is formed near the strut's leading edge,which is no doubt caused by the potential flow effects.Secondly,more severe radial migration of boundary layer flow adjacent to the strut's pressure side have been found near the nozzle's trailing edge.Such boundary layer migration is obvious,especially close to the shroud domain.Meanwhile,radial pressure gradient aggravates this phenomenon.Thirdly,velocity distribution along the strut's pressure side on nozzle's suction surface differs,which means loading variation of the nozzle.And it will no doubt cause nonuniform flowfield faced by the downstream rotor blade.

Experimental Study on Spark Ignition of Non-premixed Hydrogen Jets

The leaks of pressurized hydrogen can be ignited if an ignition source is within a certain distance from the source of the leaks, and jet ftres or explosions may take place. In this paper, a high speed camera was used to investigate the ignition kernel development, ignition probability and flame propagation along the axis of hydrogen jets, which leaked from a 3-ram-internal-diameter nozzle and were ignited by an electric spark. Experimental results indicate that for successful ignition events, the ignition delay time increases with an increase of the distance between the nozzle and the electrode. Ignitable zone of the hydrogen jets is underestimated if using the predicted hydrogen concentration along the jets centerline. The average rate of downstream flame decreases but that of the upstream flame increases with the electrode going far from the nozzle.

Velocity and Size of Droplets in Dense Region of Diesel Fuel Spray on Transient Needle Opening Condition

In order to investigate the effect of transient needle opening on early stage of spray behavior, simultaneous measurements of velocity and size of droplet were conducted by a newly developed laser 2-focus velocimeter (L2F). The micro-scale probe of the L2F was consisted of two foci with a distance of 36μm. The tested nozzle had a single hole with a diameter of 0.2 mm. The measurements of injection pressure, needle lift, and crank angle were synchronized with the spray measurement by the L2F at the position 10 mm downstream from the nozzle exit. It has been clearly shown that the velocity and size of droplet increase with needle valve opening and that the probability density distribution of droplet size can be fitted to the Nukiyama-Tanasawa distribution under the transient needle opening condition.