Papers by Keyword: Jet Angle

Abstract: The rotary control orifice, in which the relative angular openings are adjusted by the rotary motion of the spool, thus controlling the flow area and the flow passing through, is a basic control element of hydraulic control valve. It has several advantages, such as little minimal steady flow rate, good anti-contamination, small driving power, small opening and shutting shock, and etc., over the translational control orifice. The working medium is tap water. A model is developed and numerical studies are carried out to investigate the hydrodynamic characteristics of the rotary control orifice, including flow and pressure field, flow characteristics, flow torque. The relationships between the flow and the pressure drops, the efflux angle and the angular openings, the steady-state flow torque and the pressure drops as well as the angular openings are obtained. The results show that a) the orifice geometries have great effects on the efflux angle and the steady-state flow torque; b) Under the same openings and flow direction, the efflux angle is almost constant under different pressure drops. It is larger for meter-in flow than for meter-out flow and decreases with the increase of openings; c) The steady-state flow torque (including meter-in flow Tsfin and meter-out flowTsfout ) is proportional to the pressure drops and first increases and then decreases with the increase of openings, finally reaches zero at the fully opened position; d) The friction moment is proportional to the rotary speed so as the transient flow induced moment to the rotary acceleration. The in-depth study of the drag moment of rotary control orifice helps to design high performance rotary servo valve for robots. The in-depth study of the rotary control orifice provides a basis for developing high performance rotary control valve.

Abstract: The sewage diffusion is an environmental material for protecting marine environment. It plays an important role in port engineering. Its effect under deep water was carried out between different diffuser design parameters based on the hydraulic model test, and YangKou port sewage marine disposal project phase I was taken as an example. For this project, jet angle was controlled to be 0 degree, and horizontal angle was controlled to be 0 degree. It not only can ensure that sewage fully diluted mixed, also can avoid the premature convergence and sewage lifting. It is feasible for selecting large angle nozzle under deep water and there are some technical bases have been provided for other sewage marine disposal project.

Abstract: Diffusion combustion of propane and air in a rotational combustor was simulated by three-dimensional numerical model based on FLUENT. Influence of centrifugal field on the flame shapes and temperatures were discussed under various jet angles changing in the plane perpendicular to the rotational axis. The flame is compressed when the value of jet angle θ is less 90°, otherwise, the flame is stretched when |θ|>90°. When θ<90°, the deflection of flame becomes larger with an increase of θ. As contrasted to positive θ cases, the zones of high temperature in combustion chamber corresponding to negative are larger, and the maximal flame temperatures are likewise larger. The negative jet angle is useful to flame stability. External fluid is an important factor influence the distribution of temperature in combustion chamber.

Abstract: The sewage diffusion is an environmental material for protecting marine environment. It plays an important role in port engineering. Its effect under deep water was carried out between different diffuser design parameters based on the hydraulic model test, and YangKou port sewage marine disposal project phase II was taken as an example. For this project, jet angle was controlled to be 0 degree, and horizontal angle was controlled to be 0 degree. It not only can ensure that sewage fully diluted mixed, also can avoid the premature convergence and sewage lifting. It is feasible for selecting large angle nozzle under deep water and there are some technical bases have been provided for other sewage marine disposal project.

Abstract: The dining room door with going out and coming in of people and goods is often opened, heating and air-conditioning building in order to energy-saving and preventing the outdoor air on indoor environment influence, install a set of air curtain at the entrance of the dining room door to stopping the outdoor air, commonly used air curtain is ceiling type air curtain. This article in view of the gate of one area, a layer of the dining room of Hebei University of science and technology of a new campus area set up physical model of air curtain and reasonable simplification, determining the calculation area of the numerical simulation and air curtain close condition. Then adopting the UFD method to wind pressure, hot pressure and the air curtain air flowing of the local hot pressure stack of main entrance set up physical model, through the numerical simulation of air curtain different jet angle, demonstrate the air energy-saving effect, provide the reference for the choice of the air curtain.

Abstract: To reduce the cavitation occurring on valve plate of typical Swashplate piston pump, an optimization design method was introduced to quantitively analyse the accurate relationship between structural jet grooves parameters and cavitation.Using the CFD method, the sunking and discharging process in piston pump was simulated dynamically.The damp grooves structure effect on both jet angle and pressure shock were analysed visually with a series of different parametrical grooves.By establishing parametrical damp groove model, the piston pumps dynamic analysis was integrated with the technologies of CFD analysis, experimental design and approximation model, etc.The mathematical model of plunger pressure in oil back period, jet angle and structural parameters of damp groove were established in the form of second-order RSM model. The damp groove structure of valve plate was optimized on the basis of the RSM model.Test data show that the anti-cavitation performance of optimized valve plate was increased obviouslyAnd this method provided theoretical foundation for the structure design of damp groove.

Abstract: A new multi-parameter optimal inversion method for jet ratio and jet angle is established by coupling data-driven model theory with variable density anisotropic turbulent buoyant jet model in this paper. In this method, firstly the multi-parameter matching cases of jet ratio and jet angle are computed by the jet model, and the solution space of internal observation site in the computation waters is constructed by numerical simulation results. Secondly, the nonlinear relationship between state variables (dilution degree) and control variables (model multi-parameter) is established by data-driven model theory. Finally the optimal solution is obtained by inputting the needed dilution degree to the relationship. The numerical results show that multi-parameter optimal coupled inversion method is efficient for the optimal jet parameters and has advantages of jet water mixing with environment water.

Abstract: The rapid spreading of poisonous smoke is the main reason which causes death in ship fires. Ships always have long tunnels to traveling passengers or cargos. Because of their longness and straightness, smoke diffuses rapidly. Fire doors are used to stop the smoke from spreading into other parts in vessels. When the fire doors are closed, the way for evacuation is also closed. So it’s important for the professionals to develop a kind of smoke-preventing device which can let people pass by when stopping the smoke. The air curtain is a kind of smoke isolating device which is used to decrease the heat exchange in supermarket or freezer. This paper analyzes flow field, the heat control and the smoke isolating ability of air curtain used in the ships’ long tunnels with different jet angles and initial velocities. At last, a suitable angle is proposed.

Abstract: The grinding fluid can realize its function of cooling and lubricating only when it breaks through the airflow barrier around the wheel and enter into the high pressure area between wheel and workiece. The grinding fluid with different jet angles and different flow quantity has the different effect of cooling and lubricating in the grinding process. The experimental research of grinding fluid jet flow is carried out in cylindrical grinding process and the affecting mechanism of the grinding fluid injection angles and quantity on the surface integrity are analyzed based on the cylindrical grinding under the less grinding fluid conditions in this paper. It is obtained that the surface integrity of the workpiece processed at 35° fluid jet angle is superior to that of the workpiece processed at 0° fluid injection angle. It is also obtained that the more the fluid quantity is, the better the surface quality is to some extent. It provides research foundation for designing the supplying parameters of the grinding fluid and realizing the grinding process with the less grinding fluid flow.