Hydrodynamic characteristics of blowing and suction on sheet-cavitating flows around hydrofoils

2016 ◽  
Vol 114 ◽  
pp. 25-36 ◽  
Author(s):  
Pooria Akbarzadeh ◽  
Ebrahim Akbarzadeh
Author(s):  
Yoav Peles ◽  
Brandon Schneider

This report investigates the effect that hydrodynamic cavitation has on heat transfer. The fluid medium is refrigerant R-123 flowing through 227 μm hydraulic diameter microchannels. The cavitation is instigated by the inlet orifice. Adiabatic tests were conducted to study the two-phase cavitating flow morphologies and hydrodynamic characteristics of the flow. Diabatic experiments were performed resulting in surface temperatures under heat fluxes up to 213 W/cm2 and mass velocities from 622 kg/m2s to 1368 kg/m2s. Results were compared to non-cavitating flows at the same mass velocities. It was found that the cavitating flows can significantly enhance the heat transfer. The heat transfer coefficient of the cavitating flows was larger than the non-cavitating flows by as much as 84%.


2012 ◽  
Vol 226-228 ◽  
pp. 825-830
Author(s):  
Qian Kun Liu ◽  
Ye Gao

The hydrodynamic characteristics of bodies are greatly affected by cavitation. Coupling with natural cavitaion model, a multiphase CFD method is developed and is employed to simulate supercavitating and partial cavitating flows over axisymmetric bodies using FLUENT 6.2. The results of supercavitation of a disk cavitator agree well with the boundary element method (BEM), the analytical relations and available experimental results. The present computations and the BEM results are compared with experiments for partial cavitating flows over three typical axisymmetric bodies and the results are discussed. Limitations are on the pressure prediction in the cavity closure region for the BEM, although fairly good quantitative agreement is obtained for three axisymmetric bodies at most of cavitation region. The present computational model on cavitating flows are validated, offering references and bases for hydrodynamic researches.


2009 ◽  
Vol 40 (01) ◽  
Author(s):  
I Koerte ◽  
S Immler ◽  
N Alperin ◽  
C Schankin ◽  
C Grosse ◽  
...  

2020 ◽  
Vol 32 (1) ◽  
pp. 61-79
Author(s):  
Vinay Kumar Gupta ◽  
Alok Khaware ◽  
K. V. S. S. Srikanth ◽  
Jay Sanyal

Author(s):  
Emre Kahramanoglu ◽  
Silvia Pennino ◽  
Huseyin Yilmaz

The hydrodynamic characteristics of the planing hulls in particular at the planing regime are completely different from the conventional hull forms and the determination of these characteristics is more complicated. In the present study, calm water hydrodynamic characteristics of planing hulls are investigated using a hybrid method. The hybrid method combines the dynamic trim and sinkage from the Zarnick approach with the Savitsky method in order to calculate the total resistance of the planing hull. Since the obtained dynamic trim and sinkage values by using the original Zarnick approach are not in good agreement with experimental data, an improvement is applied to the hybrid method using a reduction function proposed by Garme. The numerical results obtained by the hybrid and improved hybrid method are compared with each other and available experimental data. The results indicate that the improved hybrid method gives better results compared to the hybrid method, especially for the dynamic trim and resistance. Although the results have some discrepancies with experimental data in terms of resistance, trim and sinkage, the improved hybrid method becomes appealing particularly for the preliminary design stage of the planing hulls.


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