3-D Dynamic Simulation of the High-Speed Measurement Turbine under Cavitation

2014 ◽  
Vol 644-650 ◽  
pp. 849-852
Author(s):  
Yong Chen ◽  
He Zhang ◽  
Shao Jie Ma

The external turbine can be used on underwater high-speed moving body to measure its own velocity. By establishing the rotating turbine dynamic equations and using UDF programming for secondary development on fluent software, the three-dimensional dynamic simulation of water speed measurement turbine model was achieved. Using this model, under the complex flow environment like cavitation and small attack angle, the dynamics simulation was performed and the results was analyzed to get the turbine movement characteristics. Simulation results show that the simulation model can reflect the variation in characteristics of the turbine caused by the small attack angle at cavitation situation.

Author(s):  
Guodong Sun ◽  
Xuejing Duan ◽  
Bo Hao ◽  
Afshin Davarpanah

Nitrogen oxides are considered as one of the greenhouse gases. Among the most significant emission sources for this gas is a natural gas-fired power plant. The United Nations General assembly suggested in 1988 that human activities can negatively impact weather patterns, and thus they should be controlled. This control policy can improve the efficiency of final consumers such as power plants, cars, or other energy-intensive industries. In this paper, the existing strategies and explicitly making the dry low nitrogen oxides burner reduce greenhouse gases in power plants are explored. The geometry of the burner has been produced in a three-dimensional form in GAMBIT software, and the results of the simulation have been expressed through FLUENT software. Contours of pressure, temperature, and velocity of the fluid in the furnace are also derived. It is concluded that the dry low nitrogen oxides burners plan has a better result compared with other strategies.


2014 ◽  
Vol 940 ◽  
pp. 132-135 ◽  
Author(s):  
Yi Fan Zhao ◽  
Ling Sha ◽  
Yi Zhu

Established the dynamics simulation analysis model of crane hoisting mechanism based on the theory of dynamics in Adams software, and then through the three dimensional model of lifting mechanism dynamics entities, the constraints, load, drive can be added, the motion law can be defined to simulation analysis the change of the force of wire rope, the change of displacement, velocity and acceleration of lifting weight in the lifting process. On the basis of the simulation results, it can make a great improvement for the structure of crane and provide a meaningful theoretical reference for the hoisting machinery innovation design.


2014 ◽  
Vol 11 (98) ◽  
pp. 20140541 ◽  
Author(s):  
Jialei Song ◽  
Haoxiang Luo ◽  
Tyson L. Hedrick

A three-dimensional computational fluid dynamics simulation is performed for a ruby-throated hummingbird ( Archilochus colubris ) in hovering flight. Realistic wing kinematics are adopted in the numerical model by reconstructing the wing motion from high-speed imaging data of the bird. Lift history and the three-dimensional flow pattern around the wing in full stroke cycles are captured in the simulation. Significant asymmetry is observed for lift production within a stroke cycle. In particular, the downstroke generates about 2.5 times as much vertical force as the upstroke, a result that confirms the estimate based on the measurement of the circulation in a previous experimental study. Associated with lift production is the similar power imbalance between the two half strokes. Further analysis shows that in addition to the angle of attack, wing velocity and surface area, drag-based force and wing–wake interaction also contribute significantly to the lift asymmetry. Though the wing–wake interaction could be beneficial for lift enhancement, the isolated stroke simulation shows that this benefit is buried by other opposing effects, e.g. presence of downwash. The leading-edge vortex is stable during the downstroke but may shed during the upstroke. Finally, the full-body simulation result shows that the effects of wing–wing interaction and wing–body interaction are small.


2013 ◽  
Vol 300-301 ◽  
pp. 967-973
Author(s):  
Yong Chen ◽  
He Zhang ◽  
Qi Jiang ◽  
De Zhang Shen

Combining with rotational speed measurement methods and underwater environment particularity, an independent velocity measurement scheme applicable to small underwater high-speed moving body was proposed in this paper. The structural design of the measurement device was designed and signal process method was improved, and the relationship between turbine rotational speed and speed of the body was obtained by FLUNET dynamics simulation and water tunnel experiments. Finally, the simulation and experimental results were analyzed. The results show that this method is effective and feasible within a certain range of accuracy.


Author(s):  
C. De Maesschalck ◽  
S. Lavagnoli ◽  
G. Paniagua

Tip leakage flows in unshrouded high speed turbines cause large aerodynamic penalties, induce significant thermal loads and give rise to intense thermal stresses onto the blade tip and casing endwalls. In the pursuit of superior engine reliability and efficiency, the turbine blade tip design is of paramount importance and still poses an exceptional challenge to turbine designers. The ever-increasing rotational speeds and pressure loadings tend to accelerate the tip flow velocities beyond the transonic regime. Overtip supersonic flows are characterized by complex flow patterns, which determine the heat transfer signature. Hence, the physics of the overtip flow structures and the influence of the geometrical parameters on the overtip flow require further understanding to develop innovative tip designs. Conventional blade tip shapes are not adequate for such high speed flows and hence, potential for enhanced performances lays in appropriate tip shaping. The present research aims to quantify the prospective gain offered by a fully contoured blade tip shape against conventional geometries such as a flat and squealer tip. A detailed numerical study was conducted on a modern transonic turbine rotor blade (Reynolds number is 5.5 × 105, relative exit Mach number is 0.9) by means of three-dimensional Reynolds-Averaged Navier-Stokes calculations. The novel contoured tip geometry was designed based on a 2D tip shape optimization in which only the upper 2% of the blade span was modified. This study yields a deeper insight into the application of blade tip carving in high speed turbines and provides guidelines for future tip designs with enhanced aerothermal performances.


2014 ◽  
Vol 137 (2) ◽  
Author(s):  
C. De Maesschalck ◽  
S. Lavagnoli ◽  
G. Paniagua

Tip leakage flows in unshrouded high speed turbines cause large aerodynamic penalties, induce significant thermal loads and give rise to intense thermal stresses onto the blade tip and casing endwalls. In the pursuit of superior engine reliability and efficiency, the turbine blade tip design is of paramount importance and still poses an exceptional challenge to turbine designers. The ever-increasing rotational speeds and pressure loadings tend to accelerate the tip flow velocities beyond the transonic regime. Overtip supersonic flows are characterized by complex flow patterns, which determine the heat transfer signature. Hence, the physics of the overtip flow structures and the influence of the geometrical parameters require further understanding to develop innovative tip designs. Conventional blade tip shapes are not adequate for such high speed flows and hence, potential for enhanced performances lays in appropriate tip shaping. The present research aims to quantify the prospective gain offered by a fully contoured blade tip shape against conventional geometries such as a flat and squealer tip. A detailed numerical study was conducted on a modern rotor blade (Reynolds number of 5.5 × 105 and a relative exit Mach number of 0.9) by means of three-dimensional (3D) Reynolds-averaged Navier–Stokes (RANS) calculations. Two novel contoured tip geometries were designed based on a two-dimensional (2D) tip shape optimization in which only the upper 2% of the blade span was modified. This study yields a deeper insight into the application of blade tip carving in high speed turbines and provides guidelines for future tip designs with enhanced aerothermal performances.


2016 ◽  
Vol 66 (6) ◽  
pp. 624 ◽  
Author(s):  
Anand Bhandarkar ◽  
Souraseni Basu ◽  
P. Manna ◽  
Debasis Chakraborty

<p>Combined external-internal flow simulation is required for the estimation of aerodynamic forces and moments of high speed air-breathing vehicle design. A wingless, X-tail configuration with asymmetrically placed rectangular air intake is numerically explored for which experimental data is available for different angles of attack. The asymmetrically placed air intakes and protrusions make the flow field highly three-dimensional and existing empirical relations are inadequate for preliminary design. Three dimensional Navier Stokes equations along with SST-kω turbulence model were solved with a commercial CFD solver to analyse the combined external and internal flow field of the configuration at different angles of attack. Estimated aerodynamic coefficients match well with experimental data and estimated drag coefficient are within 8.5 per cent of experimental data. Intake performance parameters were also evaluated for different angles of attack.</p>


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