Pumping Pressure Estimation Using Famous Turbulent Fluid Mechanics Equations Through Python Simulations
Luciana Claudia Martins Ferreira Diogenes
Issue:
Volume 5, Issue 4, July 2020
Pages:
53-58
Received:
21 September 2019
Accepted:
23 June 2020
Published:
8 September 2020
Abstract: One of the most important tasks when designing a pumping system is for the engineer or specialist to know the components to be used including the pumps. Knowledge about the project helps to achieve a more economical system with less risk of failure. One of these failures may result in the insertion of a pump that does not generate the proper pressure, causing the system not to function as designed. To know the pumping pressure in a system containing one pump, one long pipe and one reservoir, it is necessary to know which are the possible equations that could calculate the friction factor f more accurately to obtain the pressure. The main equation used in the turbulent regime, where Reynolds number Re (Re> 4,000), is the Colebrook equation and it is a nonlinear equation and it requires numerical programs to calculate the factor friction. Other equations are apparently simpler to employ, but are limited by the Reynolds Re number and / or the relative roughness. The purpose of this paper is to know which of the famous equations in the turbulent regime - Haaland, Blasius, Prandtl, von Karman - could be used to design a bomb when confronted with the calculations obtained by the Colebrook equation. The simulations were programmed in Python and the pumping pressure values and the error percentage were compared.
Abstract: One of the most important tasks when designing a pumping system is for the engineer or specialist to know the components to be used including the pumps. Knowledge about the project helps to achieve a more economical system with less risk of failure. One of these failures may result in the insertion of a pump that does not generate the proper pressu...
Show More
The Flow Field Analysis and Structure Optimization of Large Diameter Butterfly Valve
Issue:
Volume 5, Issue 4, July 2020
Pages:
59-63
Received:
24 August 2020
Accepted:
11 September 2020
Published:
21 September 2020
Abstract: The large diameter butterfly valve used in Qinghai Naqu hydropower station was subjected to strong vibration when the opening was small. In view of the phenomenon of strong vibration and damage of the valve, the fluid theory analysis is carried out and the appropriate mathematical model of fluid analysis is selected. This paper established the flow model of butterfly valve for different opening degrees with the 2D drawings and simulated the flow field by using CFX software. Through numerical simulation, the flow field characteristics of the valve under different opening degrees are obtained, and it is found that the valve failure is caused by vortex street effect. The results of numerical analysis show that the vortex are the most strong in the range of 5% to 30% and The vortex street phenomenon is the strongest at 5% opening. When the opening is greater than 30%, the vortex street effect decreases gradually. Meanwhile, the reason of vortex street effect is that the structure of butterfly plate is complex, and an improved structure was given and the results of numerical analysis show that the vortex effect decreased significantly for the new one. This new structure can effectively prevent the vortex resonance and give an example for the new design of a large butterfly valve.
Abstract: The large diameter butterfly valve used in Qinghai Naqu hydropower station was subjected to strong vibration when the opening was small. In view of the phenomenon of strong vibration and damage of the valve, the fluid theory analysis is carried out and the appropriate mathematical model of fluid analysis is selected. This paper established the flow...
Show More
