CONCEPTUAL DESIGN AND STUDY OF FLOW THROUGH A DUAL BELL NOZZLE AT DIFFERENT ALTITUDES USING COMPUTATIONAL FLUID DYNAMICS

2021 ◽  
Vol 11 (3) ◽  
pp. 38
Author(s):  
SAI RAJA CHADA JITHENDRA ◽  
DEEPAK AKELLA SRI RAM ◽  
SRINIVAS BASWANTH PAPPULA SASHENDRA ◽  
NATHIPAM GANESH ◽  
◽  
...  
Dynamics ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 9-17
Author(s):  
Andrea Natale Impiombato ◽  
Giorgio La Civita ◽  
Francesco Orlandi ◽  
Flavia Schwarz Franceschini Zinani ◽  
Luiz Alberto Oliveira Rocha ◽  
...  

As it is known, the Womersley function models velocity as a function of radius and time. It has been widely used to simulate the pulsatile blood flow through circular ducts. In this context, the present study is focused on the introduction of a simple function as an approximation of the Womersley function in order to evaluate its accuracy. This approximation consists of a simple quadratic function, suitable to be implemented in most commercial and non-commercial computational fluid dynamics codes, without the aid of external mathematical libraries. The Womersley function and the new function have been implemented here as boundary conditions in OpenFOAM ESI software (v.1906). The discrepancy between the obtained results proved to be within 0.7%, which fully validates the calculation approach implemented here. This approach is valid when a simplified analysis of the system is pointed out, in which flow reversals are not contemplated.


Author(s):  
Heonil Kim ◽  
Jonghark Park ◽  
Byungchul Lee ◽  
Heetaek Chae ◽  
Youngki Kim

A simple I-125 generating device at the research reactor, HANARO, is developed. Xenon-124 gas circulates continuously in the generator producing I-125 by neutron capture and the I-125 is adsorbed at the upper part of the generator, which is to be chemically recovered in a hot-cell. The continuous xenon circulation technology is devised by the design of the generator structure with the consideration of thermal hydraulics and neutron physics involved. A computational fluid dynamics technique is used for the conceptual design of the generator.


Author(s):  
M J King ◽  
T David ◽  
J Fisher

The effect of leaflet opening angle on flow through a bileaflet mechanical heart valve has been investigated using computational fluid dynamics (CFD). Steady state, laminar flow for a Newtonian fluid at a Reynolds number of 1500 was used in the two-dimensional model of the valve, ventricle, sinus and aorta. This computational model was verified using one-dimensional laser Doppler velocimetry (LDV). Although marked differences in the flow fields and energy dissipation of the jets downstream of the valve were found between the CFD predictions and the three-dimensional experimental model, both methods showed similar trends in the changes of the flow fields as the leaflet opening angle was altered. As the opening angle increased the area of recirculating fluid downstream of the leaflets, the pressure drop across the valve and the volumetric flow rate through the outer orifice decreased. For opening angles greater than 80° the jet through the outer orifice recombined with the central jet downstream of the leaflet; for an opening angle of 78° the jet through the outer orifice impinged on the aortic wall before recombining with the central jet. This study suggests that the opening angle has a marked effect on the flow downstream of the bileaflet mechanical heart valve and that valves with opening angles greater than 80° are preferable.


2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Bhavesh D. Gajbhiye ◽  
Harshawardhan A. Kulkarni ◽  
Shashank S. Tiwari ◽  
Channamallikarjun S. Mathpati

Author(s):  
Sławomir Dykas ◽  
Mirosław Majkut ◽  
Krystian Smołka ◽  
Michał Strozik

This study presents experimental and numerical testing of the steam condensing flow through a linear blade cascade made of blades of a 200 MW steam turbine last stage stator. The tests were carried out on an in-house laboratory stand and using an in-house numerical code modelling the water vapour flow with homo- and heterogeneous condensation. Additionally, this paper presents a comparison of calculations of a flow field modelled by means of a single-fluid model using both an in-house computational fluid dynamics code and the commercial Ansys CFX v16.2 software package. The aim of the research was to identify difficulties involved by comparing the numerical modelling results with the experimental data for a linear blade cascade. The experimental results, which are very well supplemented by those obtained from numerical computations, may be used to validate computational fluid dynamics codes.


2012 ◽  
Vol 195-196 ◽  
pp. 577-582
Author(s):  
Fang Xu ◽  
Jiao Liao Chen ◽  
Qin Lin Ai ◽  
Qi Chen

Hydraulic resistance of water flow in the xylem is mainly caused by Pits. Pits between vessels play an important role in the water transport of plant. The pit membrane worked as porous, the water flow through pit is modeled using CFD(Computational fluid dynamics) approach of low k-ε turbulence. Consiedered the deflection of homogeneous membrane affected by pressure difference, the pit hydraulic resistance calculated according to simulation results is consisent with hydraulic resistance value from direct measurements, which indicated that the model can provide reliable estimation the flow of water through pit.


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