外文翻譯----三維注射成型流動模擬的研究-其他專業(yè)(編輯修改稿)
2025-02-24 09:08 本頁面
【文章內(nèi)容簡介】 to form the discretized global momentum equations and the velocity may be expressed as following where the nodal pressure coefficients are defined as where represent global velocity coefficient matrices in the direction of x, y, z coordinate respectively. denote the nodal pressure coefficients the direction of x, y, z coordinate respectively. The nodal values for are obtained by assembling the elementbyelement contributions in the conventional manner. N， is element interpolation and i means global node number and j , is for a node, the amount of the nodes around it. Pressure Equation Substitution of the velocity expressions (2) into discretized continuity equation, which is discretized using Galerkin method， yields element equation for pressure: 56 The element pressure equations are assembled the conventional manner to form the global pressure equations． Boundary Conditions In cavity wall, the no slip boundary conditions are employed, . On an inlet boundary, Velocity Update After the pressure field has been obtained， the velocity values are updated using new pressure field because the velocity field obtained by solving momentum equations does not satisfy continuity equation． The velocities are updated using the following relations The overall procedure for fluid flow calculations is relaxation iterative， as shown in and the calculation is stable without pressure oscillation． The Tracing of the Flow Fronts The flow of fluid in the cavity is unsteady and the position of the flow fronts values with time． Like in model, in this paper, the control volume method is employed to trace the position of the flow fronts after the FAN(Flow Analysis Network)[6]. But 3D control volume is a special volume and more plex than the 2D control volume． It is required that 3D control volumes of all nodes fill the part cavity without gap and hollow space. Two 3D control volumes are shown in Fig． 2． 華東交通大學理工學院畢業(yè)設(shè)計（論文） 57 4 Results and Discussion The test cavity and dimensions are shown in (a)． The selected material is ABS780 from Kumbo. The parametric constants corresponding to then, γ,B, Tb and β of the fiveconstant Crosstype Viscosity model are 0． 2638, 4． 514 le4 Pa, le7 Pa *S, 1． 12236 1e4K， 0． 000 Pa1． Injection temperature is 45℃ ， mould temperature is 250℃ , injection flow rate is 44． 82 cu. cm／ s. The meshed 3D model of cavity is shown in Fig. 3(b). 58 “Fountain flow” is a typical flow phenomenon during filling． When the fluid is injected into a relatively colder mould， solid layer is formed in the cavity walls because of the diffusion cooling， so the shear near the walls takes place and is zero in the middle of cavity, and the fluid near the walls deflects to move toward the walls． The fluid near the center moves faster than the
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