Semi-Empirical Study of Water Flow Through Vortex Triodes and Performance Optimization

2015 ◽  
Vol 137 (12) ◽  
Author(s):  
Guido Belforte ◽  
Andrea Manuello Bertetto ◽  
Luigi Mazza
Keyword(s):  
Empirical Study ◽  
Water Flow ◽  
Performance Optimization ◽  
Empirical Formula ◽  
Test Bench ◽  
Control Flow ◽  
Operating Conditions ◽  
Flow Through ◽  
And Performance ◽  
Semi Empirical

A study was carried out to evaluate behavior and performance of vortex triodes. In particular, the study investigated the geometries and operating conditions which minimize the control flow capable of intercepting the supply flow. The study was conducted experimentally using a specially designed test bench on prototypes operating with water. The geometric parameters which influence vortex valve performance were identified and varied so as to minimize the ratio between control and supply flows. The paper presents a semi-empirical formula to predict vortex valve performance. In particular, the formula takes valve outlet geometry and the shape of outlet diffusers into account.

On the vibration analysis of off-road vehicles: Influence of terrain deformation and irregularity

2018 ◽  
Vol 24 (22) ◽  
pp. 5418-5436 ◽  
Author(s):  
Giulio Reina ◽  
Antonio Leanza ◽  
Arcangelo Messina
Keyword(s):  
Performance Optimization ◽  
Operating Conditions ◽  
Vehicle Body ◽  
Surface Irregularity ◽  
Parameter Study ◽  
Road Vehicles ◽  
Wheel Rolling ◽  
And Performance ◽  
Underlying Mechanisms ◽  
The Impact

Surface irregularity acts as a major excitation source in off-road driving that induces vibration of the vehicle body through the tire assembly and the suspension system. When adding ground deformability, this excitation is modulated by the soil properties and operating conditions. The underlying mechanisms that govern ground behavior can be explained and modeled drawing on Terramechanics. Based on this theory, a comprehensive quarter-car model of off-road vehicle is presented that takes into account tire/soil interaction. The model can handle the general case of compliant wheel rolling on compliant ground and it allows ride and road holding performance to be evaluated in the time and frequency domain. An extensive set of simulation tests is included to assess the impact of various surface roughness and ground deformability through a parameter study, showing the potential of the proposed model to describe the behavior of off-road vehicles for design and performance optimization purposes.

A Theoretical and Experimental Study of a Liquid-Lubricated Hydrostatic Journal Bearing

1968 ◽  
Vol 183 (1) ◽  
pp. 647-662 ◽  
Author(s):  
C. Betts ◽  
W. H. Roberts
Keyword(s):  
Journal Bearing ◽  
Reynolds Numbers ◽  
Liquid Sodium ◽  
Working Fluid ◽  
Design Problems ◽  
Static Performance ◽  
Flow Through ◽  
Temperature Liquid ◽  
And Performance ◽  
Semi Empirical

The use of mechanical pumps for circulating high-temperature liquid-sodium coolant in nuclear-powered fast reactors emphasizes the problem of designing suitable bearings. This paper presents a semi-empirical theory which describes the (static) performance of a hydrostatic jet journal bearing for such applications where the flow through the bearing is predominantly turbulent. The theory covers both viscous and turbulent regimes of flow. In the presentation non-dimensional groups are plotted to facilitate direct application of the theory to specific design problems. Experiments using paraffin and water as the working fluid are described; Reynolds numbers of approximately 1700 and 7000 respectively were achieved—compared with Re in excess of 20 000 likely to be encountered in practice. The design and performance of an 8 in diameter bearing for a 6000 gal/min mechanical sodium pump prototype are briefly described.

Design, Modeling, and Performance Optimization of a Reversible Heat Pump/Organic Rankine Cycle System for Domestic Application

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Sylvain Quoilin ◽  
Olivier Dumont ◽  
Kristian Harley Hansen ◽  
Vincent Lemort
Keyword(s):  
Heat Pump ◽  
Performance Optimization ◽  
Low Cost ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Operating Conditions ◽  
Working Fluid ◽  
Thermal Source ◽  
Cycle System ◽  
And Performance

In this paper, an innovative system combining a heat pump (HP) and an organic Rankine cycle (ORC) process is proposed. This system is integrated with a solar roof, which is used as a thermal source to provide heat in winter months (HP mode) and electricity in summer months (ORC mode) when an excess irradiation is available on the solar roof. The main advantage of the proposed unit is its similarity with a traditional HP: the HP/ORC unit only requires the addition of a pump and four-way valves compared to a simple HP, which can be achieved at a low cost. A methodology for the optimal sizing and design of the system is proposed, based on the optimization of both continuous parameters such as heat exchanger size or discrete variables such as working fluid. The methodology is based on yearly simulations, aimed at optimizing the system performance (the net yearly power generation) over its whole operating range instead of just nominal sizing operating conditions. The simulations allow evaluating the amount of thermal energy and electricity generated throughout the year, yielding a net electric power output of 3496 kWh throughout the year.

The Study of Marine Gas Turbine Power System Simulation Software Development

2013 ◽  
Vol 300-301 ◽  
pp. 166-171 ◽  
Author(s):  
Lei Cao ◽  
Shu Ying Li ◽  
Zhi Tao Wang
Keyword(s):  
Power System ◽  
System Design ◽  
Engineering Design ◽  
Gas Turbine ◽  
Performance Optimization ◽  
Dynamic Performance ◽  
Simulation Software ◽  
Operating Conditions ◽  
And Performance ◽  
The Mathematical Model

This software is aimed at providing engineering design personnel who are engaged in marine gas turbine power system design and performance optimization with a software platform for concentrated design and management. First, the mathematical model of the sub-shaft gas turbine was established using volume inertia and rotor inertia method. And then the relative non-linear simulation module base of all components was built based on MATLAB/Simulink. Second, in order to develop this extensible simulation software for the study on the marine gas turbine overall performance, a human-computer interface was cultivated too based on MATLAB/GUI. This software provides the functions of analyzing dynamic performance of the marine gas turbine power system in both on-design and off-design operating conditions. It offers engineering design personnel an extensible and useful GUI platform in gas turbine system design and performance optimization.

Impact of water quality and reactor hydrodynamics on wastewater disinfection by UV, use of CFD modeling for performance optimization

1998 ◽  
Vol 38 (6) ◽  
pp. 71-78 ◽  
Author(s):  
M. L. Janex ◽  
P. Savoye ◽  
Z. Do-Quang ◽  
E. Blatchley ◽  
J. M. Laîné
Keyword(s):  
Water Quality ◽  
Performance Optimization ◽  
Flow Reactor ◽  
Operating Conditions ◽  
Cfd Modeling ◽  
Uv Reactor ◽  
Wastewater Disinfection ◽  
Flow Through ◽  
Solids Content

In order to ensure reliable operating conditions for adequate wastewater disinfection in a UV reactor, two aspects were investigated as having a critical impact on the disinfection performances: water quality and hydrodynamics of the water flow through the system. Tests performed with a collimator on several wastewater effluents enabled us to relate the UV inactivation to the total suspended solids content of the water to be treated, the influence being decisive under 5 mg/l TSS. On the other hand, a CFD (Computational Fluid Dynamics) numerical tool was used to provide an accurate characterization of the flow pattern within a vertical flow reactor. On the basis of such modeling, modifications in the geometry of the reactor could be proposed aiming at reducing zones of low dose and therefore improving disinfection performances. Side-by-side experimental comparisons between modified and unmodified pilots enabled us to validate that approach.

scholarly journals Analysis of the NOx storage behaviour during cold start of modern SCR flow-through substrates and SCR on-filter substrates

2021 ◽  
Author(s):  
Deinhofer Lukas ◽  
Maurer Michael ◽  
Barnstedt Gert ◽  
Keber Andreas
Keyword(s):  
Water Vapor ◽  
Test Bench ◽  
Adsorbed Water ◽  
Cold Start ◽  
Space Velocity ◽  
Operating Conditions ◽  
Exhaust Pipe ◽  
Scr Catalysts ◽  
Synthetic Gas ◽  
Flow Through

AbstractSelective catalytic reduction (SCR) systems are the state-of-the-art technology to reduce nitrogen oxide emissions (NOx) of modern diesel engines. The system behaviour is well understood in the common temperature working area. However, the system properties below light-off temperature are less well known and offer a wide scope for further investigations. Vehicle measurements show that under specific conditions during cold start, NOx can be partially stored and converted on on-filter and flow-through SCR catalysts. The purpose of this work was in a first step to analyse the main influence parameters on the NOx storage behaviour. Therefore, synthetic gas test bench measurements have been carried out, varying the gas concentrations, temperature, and gas hourly space velocity (GHSV). These investigations showed that the NOx storage effect strongly depends on the NH3 level stored in the catalyst, GHSV, the adsorbed water (H2O) on the catalyst, and the temperature of the catalyst. Further influence parameters such as the gas composition with focus on carbon monoxide (CO), short-chain hydrocarbons and long-chain hydrocarbons have been analysed on a synthetic gas test bench. Depending on operating conditions, a significant amount of NOx can be stored on a dry catalyst during the cold start phase. The water vapor from the combustion condenses on the cold exhaust pipe during the first seconds, or up to a few minutes after a cold start. As the water vapor reaches the surface of the catalyst, it condenses and adsorbs onto it, leading to a sudden temperature rise. This exothermal reaction causes the stored NOx to be desorbed, and furthermore it is partially reduced by the NH3 stored in the catalyst.

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