Ali Safari Variani¹, Ali Dastamoz¹, Sajad Zare², Ahmad Nikpey¹, Saeid Ahmadi^1,*

Sound & Vibration, Vol.54, No.1, pp. 43-55, 2020, DOI:10.32604/sv.2020.08636

Abstract This work investigated multiple jet nozzles with various geometrical shape, number of exits, and material on reducing noise radiated from jet flows. Nozzles are categorized in two groups with few and many exit numbers, each with various exit shapes, slot and circular, and geometry. Firstly, nozzles are designed and then fabricated by a 3D printer, Form Labs, Form2USA, with polymeric resin. Also, the nozzle with the most noise reduction made of stainless steel. Noise and air thrust were measured at three air pressure gauges, 3, 5, 7 BAR and directions from nozzle apex, 30°, 90°, 135°. Nozzles with slot exit… More >

H. T. Wang, L. Shi

The International Conference on Computational & Experimental Engineering and Sciences, Vol.19, No.1, pp. 11-12, 2011, DOI:10.3970/icces.2011.019.011

Abstract A three-dimensional fast boundary element solver is developed for the shape optimization of nozzles of nuclear reactor pressure vessels (RPVs). In a RPV, pressure and mechanical loads may lead to high stress concentration due to the discontinuity of the structure, especially at the inner surface of the cold/hot legs. This work aims to minimize these stress concentrations by optimizing the geometry of the openings using modern shape optimization techniques and fast boundary element method. Shape optimization methods based on the principle of biological adaptive growth are incorporated into a boundary element method program and used to optimize the design of… More >

Haojun Peng^1,*, Zhongwei Wu¹, Jinbing Xia¹, Bolin Dong¹, Yuntao Peng², Linghe Wang³, Xingxing Ma³, Wei Shen³

CMES-Computer Modeling in Engineering & Sciences, Vol.120, No.3, pp. 799-813, 2019, DOI:10.32604/cmes.2019.06950

Abstract In this paper, numeric simulations are performed for three dimension models built according to actual surface cleaner in airport runway rubber mark cleaning vehicle using ANSYS FLUENT software on the basis of previous research finished by the authors. After analyzing the simulated flow fields under different standoff distances between nozzle outlet and runway surface and different discharge pressures at nozzle outlet, the relationships of normal stress and shear stress at striking point to outlet pressure and standoff distance are obtained. Finally, the most appropriate discharge pressure at nozzle outlet for the studied surface cleaner model is found, and this will… More >

W. A. El-Askary^1,2, S. A. Wilson², A. Hegab²

CMES-Computer Modeling in Engineering & Sciences, Vol.76, No.3&4, pp. 235-266, 2011, DOI:10.3970/cmes.2011.076.235

Abstract In the present work, a complete simulation of reactive flow in the combustion chamber of a rocket motor equipped with convergent-divergent nozzle has been introduced. The model describes the combustion process inside the combustion chamber considering a steady premixed reactant gas injected through side porous walls of the combustion chamber. The products flow through a convergent-divergent nozzle with adiabatic impermeable walls. The reactants are treated as two-dimensional, multi-components, turbulent compressible flow. The local properties of the mixture are calculated and updated during the solution process. At the boundary of the combustion chamber, a constant mass flux and predefined properties are… More >

Hui-Fen Guo^1,2, Bin-Gang Xu^1,3, Sheng-Yan Li¹, Chong-Wen Yu²

CMES-Computer Modeling in Engineering & Sciences, Vol.80, No.2, pp. 87-112, 2011, DOI:10.3970/cmes.2011.080.087

Abstract Three-dimensional transient simulation is presented for swirling recirculating flow in a nozzle with a slotted-tube (different grooves) and the effect of the groove number is also investigated. The numerical results on the streamline angles are validated by experimental visualization using the surface oil flow technology. In the downstream center of the injectors, the vortex breakdown experiences a transition from bubble- to spiral- breakdown as time is increased. For all cases under study, as the sizes of two recirculation zones near the injector upstream wall and the step retain almost constant, the spiral breakdown shows a periodic development. The more the… More >

Hui-Fen Guo^1,2, Bin-Gang Xu^1,3

CMES-Computer Modeling in Engineering & Sciences, Vol.61, No.3, pp. 201-222, 2010, DOI:10.3970/cmes.2010.061.201

Abstract A numerical method is developed for modeling the dynamics of a flexible fiber immersed in a compressible swirling flow. The modeling approach is based on combining an Eulerian finite volume formulation for the fluid flow and a Lagrangian small-deformation formulation for the dynamics of the fiber. The fiber is modeled as a chain of beads connected through mass-less rods. The bending and twisting deformation of the fiber are represented by the displacements of the successive beads. A computational strategy is proposed for the computation of the fluid parameters at the center of discrete fiber sections. To deal with the fiber-wall… More >

Shuce Zhang¹, Xueheng Tao^1,2,3, Jinshi Lu^1,2, Xuejun Wang^1,2, ZhenhuaZeng⁴

FDMP-Fluid Dynamics & Materials Processing, Vol.11, No.2, pp. 143-155, 2015, DOI:10.3970/fdmp.2015.011.143

Abstract Three different kinds of nozzles, normally used in industrial processes for the cleaning of material surface by means of water jets at high pressure (a Cylindrical Contracting, a Taper Contracting and Stepped nozzle), are numerically simulated with the express intent to optimize the related efficiency (cleaning effectiveness). Although some of them are found to display interesting properties, simulation results indicate that a helix nozzle displays the best jetting performances. It is shown that, as compared to improvements obtained by simply changing the jetting angle, revolving the fluid released from the helix nozzle can be used to create a grinding wheel… More >