Hydrodynamic design of an advanced submerged propulsion

2019 ◽  
Vol 233 (18) ◽  
pp. 6367-6382
Author(s):  
Jing-Wei Jiang ◽  
Wei-Xi Huang
Keyword(s):  
Stokes Equations ◽  
Navier Stokes ◽  
Design Parameters ◽  
Reynolds Average Navier Stokes ◽  
Navier Stokes Equations ◽  
Mathematical Algorithm ◽  
Cavitation Performance ◽  
Intermediate Section ◽  
Thrust And Torque ◽  
Reynolds Average

A new kind of advanced submerged propulsion is automatically modeled and analyzed based on the hydrodynamic and cavitation performance. A mathematical algorithm is proposed to describe the fusion-duct, which is controlled by several design parameters, including section diameters, section lengths, and inlet shape and aspect ratio. The hydrodynamic performances of 13 cases with different parameter combinations are numerically simulated. The simulation is carried out by solving the Reynolds Average Navier-Stokes equations with STAR-CCM+, and the SST k-ω turbulence model is applied. The curves of rotor thrust and torque, stator thrust and duct resistance, along with efficiency and merit coefficient are obtained as functions of the advance coefficient and are compared for different cases. Meanwhile, the pressure distribution on both sides of the rotor and the flow field of intermediate section are systematically analyzed. To guide future designs, an impact factor is further defined and calculated to quantify the effects of different parameters. The results indicate that the section diameters have the most significant influence on hydrodynamic and cavitation performances.

Dynamic Stall Control by Undulatory Deformation

2013 ◽  
Vol 444-445 ◽  
pp. 299-303
Author(s):  
Lan Ge ◽  
Wen Rong Hu
Keyword(s):  
Stokes Equations ◽  
Dynamic Stall ◽  
Navier Stokes ◽  
Reynolds Average Navier Stokes ◽  
Navier Stokes Equations ◽  
Stall Angle ◽  
Stall Control ◽  
Reynolds Average ◽  
High Angles Of Attack ◽  
Better Than

Dynamic stall can delay the stall of wings and airfoils that are rapidly pitched beyond the static stall angle. A new method of active dynamic stall control by the undulatory foil was proposed in this paper. The study was based on solving unsteady Reynolds-Average Navier-Stokes equations. Comparisons of the effectiveness of pitching foils and undulatory foils on dynamic stall control in both light stall and deep stall were conducted. The undulatory foils with various controllable parameters were further discussed. The results showed that the performance of undulatory foils is much better than that of the rigid pitching foil at high angles of attack either in the light stall or in the deep stall situation.

Numerical Investigation of the Effect of Balancing-Hole on the Axial Force of a Partial Emission Pump

2014 ◽  
Author(s):  
Zhang Lisheng ◽  
Jiang Jin ◽  
Xiao Zhihuai ◽  
Li Yanhui
Keyword(s):  
Axial Force ◽  
Stokes Equations ◽  
Dominant Role ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Design Parameters ◽  
Navier Stokes Equations ◽  
Computational Fluid Dynamics Cfd ◽  
The Cost

In this paper numerical simulations were conducted to analyze the effects of design parameters and distribution of balancing-hole on the axial-force of a partial emission pump. The studied pump is a single stage pump with a Barske style impeller. Based on the original impeller, we designed 7 pumps with different balancing-hole diameters and the partial emission pump equipped with different impellers were simulated employing the commercial computational fluid dynamics (CFD) software Fluent 12.1 to solve the Navier-Stokes equations for three-dimensional steady flow. A sensitivity analysis of the numerical model was performed with the purpose of balancing the contradiction of numerical accuracy and the cost of calculation. The results showed that, with increasing of the capacity, the axial force varies little. The diameter of the inner balancing-hole plays a dominant role of reducing axial-force of partial emission pump, the axial-force decreases with increasing of inner balancing-hole diameter on the whole range of operation, the axial-force of impeller without inner balancing-hole is approximately 3 times larger than that of impeller with inner balancing-hole. While the diameter of outer balancing-hole has a reverse effects compared with that of inner balancing-hole. With increasing of outer balancing-hole, the axial force increases accordingly.

Design and Experimental Study on the Surge Performance Improvement by the Effects of Bleed Slot Casing of a Centrifugal Compressor

2014 ◽  
Author(s):  
Hong Won Kim ◽  
Jae Hoon Chung ◽  
Hyo Seong Lee ◽  
Min Ouk Choi
Keyword(s):  
Centrifugal Compressor ◽  
Stokes Equations ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Design Parameters ◽  
Navier Stokes Equations ◽  
Operating Range ◽  
Surge Margin ◽  
Commercial Code

The primary design goal of a compressor is focused on improving efficiency. Secondary objective is to widen the compressor’s operating range. This paper presents a numerical and experimental investigation of the influence of the bleed slot to enlarge operating range for the 1.2MW class centrifugal compressor installed in a turbocharger. The main design parameters of the bleed slot casing are upstream slot position, inlet pipe slope, downstream slot position and width. The DOE (design of experiment) method was carried out to optimize the casing design. Numerical analyses were done by the commercial code ANSYS-CFX based on the three dimensional Reynolds-averaged Navier-Stokes equations. From the analysis, as the downstream slot position and width are smaller and upstream position is located away from impeller inlet, efficiency and pressure ratio are increased. Experimental works were done with and without the bleed slot casing. The simulation results were in good agreement with the test data. In case without the bleed slot casing, the surge margin value came out to be only 11.8% but with the optimized bleed slot design, the surge margin reached 23%. Therefore, the surge margin increase of 11.2% was achieved.

Spent Flow Effects of Multiple Micro-Jet Impingement Cooling Models

2015 ◽  
Author(s):  
Afzal Husain ◽  
Nasser A. Al-Azri ◽  
Abdus Samad ◽  
Sun-Min Kim ◽  
Kwang-Yong Kim
Keyword(s):  
Pressure Drop ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Thermal Characteristics ◽  
Jet Impingement ◽  
Navier Stokes ◽  
Maximum Temperature ◽  
Design Parameters ◽  
Comparative Performance ◽  
Navier Stokes Equations

The current study investigated comparative performance of wall-confined and unconfined multiple micro-jet impingement heat sink models for electronic cooling applications. The pressure-drop and thermal characteristics were determined for steady incompressible and laminar flow by solving three-dimensional Navier–Stokes equations. Several parallel and staggered micro-jet configurations consisting of a maximum of 16 jet impingements were tested. The effectiveness of various micro-jet configurations, i.e., inline 2×2, 3×3 and 4×4 jets, and staggered 5-jet and 13-jet arrays with nozzle diameters 50, 76, and 100 μm, were analyzed at various flow rates for the maximum temperature-rise, pressure-drop and heat transfer coefficient characteristics. Two design parameters, the ratio of jet diameter to height of the channel and jet distribution, were chosen for comparative performance analysis.

Effect of Turbulence Modeling on VIV Numerical Simulation

2005 ◽  
Author(s):  
Juan B. V. Wanderley ◽  
Gisele H. B. Souza ◽  
Carlos Levi
Keyword(s):  
Numerical Method ◽  
Compressible Flows ◽  
Turbulence Modeling ◽  
Stokes Equations ◽  
Turbulence Models ◽  
Circular Cylinders ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Reynolds Average

Author’s previous work Wanderley [1] presented an efficient numerical method to investigate VIV phenomenon on circular cylinders. The numerical model solves the unsteady Reynolds Average Navier–Stokes equations for slightly compressible flows using the Beam–Warming implicit factored scheme. In the present work, the effect of the turbulence model on the results is evaluated for both Baldwin Lomax and k-ε models. To demonstrate the quality of the numerical method, results for the transversal oscillation of a cylinder laterally supported by spring and damper are compared with experimental data. The application of the turbulence models showed the much better agreement of the k-ε model with the experimental results.

Dissipation of intense vortices

2009 ◽  
Vol 87 (6) ◽  
pp. 685-689 ◽  
Author(s):  
Yasser Aboelkassem
Keyword(s):  
Steady State ◽  
Stokes Equations ◽  
Similarity Transformation ◽  
Navier Stokes ◽  
Time Decay ◽  
Navier Stokes Equations ◽  
Mathematical Algorithm ◽  
Vortex Model ◽  
Burgers Vortex ◽  
Time Analogy

In this article, we extend the space-time analogy shared by viscous vortices to generalize the dissipation of intense vortices Vatistas and Aboelkassem (Am. Inst. Aeronaut. Astronaut. J. 44, 912 (2006)). The main objective is to layout a mathematical algorithm that can be used to transform vortices into their dissipative phase or into a steady-state counterpart via a similarity transformation to Navier–Stokes equations. The method is applied to examine the time decay of eddies that belong to the Oseen-like concentrated type of viscous vortices. The steady-state Burgers’ vortex model was used to validate the transformation approach. This analysis shows that, upon variable transformation, Burgers’ vortex model has changed into the Oseen–Lamb class of decaying vortices. The approach is simple, general, and applicable to all kinds of viscous incompressible vortices like those of Sullivan, Rott, Bellamy-Knights, Vatistas, and Scully.

scholarly journals CFD Analysis of the First-Stage Rotor and Stator in a Two-Stage Mixed Flow Pump

2005 ◽  
Vol 2005 (1) ◽  
pp. 23-29 ◽  
Author(s):  
Steven M. Miner
Keyword(s):  
Stokes Equations ◽  
Flow Coefficient ◽  
Navier Stokes ◽  
Design Parameters ◽  
Mixed Flow ◽  
Two Stage ◽  
Navier Stokes Equations ◽  
Pressure Profiles ◽  
Turbulence Effects ◽  
Flow Pump

A commercial computational fluid dynamics (CFD) code is used to compute the flow field within the first-stage rotor and stator of a two-stage mixed flow pump. The code solves the 3D Reynolds-averaged Navier-Stokes equations in rotating and stationary cylindrical coordinate systems for the rotor and stator, respectively. Turbulence effects are modeled using a standardk−εturbulence model. Stage design parameters are rotational speed890 rpm, flow coefficientφ=0.116, head coefficientψ=0.094, and specific speed2.01(5475 US). Results from the study include velocities, and static and total pressures for both the rotor and stator. Comparison is made to measured data for the rotor. The comparisons in the paper are for circumferentially averaged results and include axial and tangential velocities, static pressure, and total pressure profiles. Results of this study show that the computational results closely match the shapes and magnitudes of the measured profiles, indicating that CFD can be used to accurately predict performance.

Analysis of Loads and Response on Flexible Riser under the Combined Effects of Wave and Current

2015 ◽  
Vol 723 ◽  
pp. 120-124 ◽  
Author(s):  
Zi Xin Wu ◽  
Ren Qing Zhu ◽  
Si Qi Gu ◽  
Zhi Ping Xia ◽  
Yang Luo ◽  
...  
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Flexible Riser ◽  
Navier Stokes Equations ◽  
Volume Method ◽  
System Coupling ◽  
Reynolds Average ◽  
Viscid Fluid ◽  
Module System

A three dimensional computational model is established for the analysis of loads and response of flexible riser in a wave-current coexisting environment. The viscid fluid is assumed incompressible. The flow field is described by continuity equation and Reynolds Average Navier-Stokes equations and solved with the discretization of Finite-Volume Method. The structure responses are analyzed employing finite element method based on three dimensional solid element. The loads and response are calculated through the CFD module System Coupling in software package ANSYS14.5. The results show that the vibration equilibrium position of riser offsets along with the direction of current when wave and current are in the same direction, the response of the riser is larger than that only in wave, the vibration amplitude increases with the current and the results are opposite to the above when wave and current has the opposite direction.

scholarly journals Numerical Identification of Key Design Parameters Enhancing the Centrifugal Pump Performance: Impeller, Impeller-Volute, and Impeller-Diffuser

2011 ◽  
Vol 2011 ◽  
pp. 1-16 ◽  
Author(s):  
Massinissa Djerroud ◽  
Guyh Dituba Ngoma ◽  
Walid Ghie
Keyword(s):  
Centrifugal Pump ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Design Parameters ◽  
Navier Stokes Equations ◽  
Wall Functions ◽  
Pump Performance ◽  
Ansys Cfx ◽  
Pump Head

This paper presents the numerical investigation of the effects that the pertinent design parameters, including the blade height, the blade number, the outlet blade angle, the blade width, and the impeller diameter, have on the steady state liquid flow in a three-dimensional centrifugal pump. Three cases were considered for this study: impeller, combined impeller and volute, and combined impeller and diffuser. The continuity and Navier-Stokes equations with the k-ε turbulence model and the standard wall functions were used by means of ANSYS-CFX code. The results achieved reveal that the selected key design parameters have an impact on the centrifugal pump performance describing the pump head, the brake horsepower, and the overall efficiency. To valid the developed approach, the results of numerical simulation were compared with the experimental results considering the case of combined impeller and diffuser.

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