scholarly journals Optimization of injected radiotracer volume for flow rate measurement in closed conduits

2020 ◽  
Vol 74 (5) ◽  
pp. 305-312
Author(s):  
Miroslav Pavlovic ◽  
Marijana Pantovic-Pavlovic ◽  
Pavel Bartl ◽  
Jasmina Stevanovic ◽  
Bojan Radak
Keyword(s):  
Flow Rate ◽  
Fluid Velocity ◽  
Plug Flow ◽  
Volumetric Flow Rate ◽  
Pilot Scale ◽  
Quality Performance ◽  
Flow Meters ◽  
Injection Volume ◽  
In Situ Calibration ◽  
Flow Quality

In chemical processes it is essential that the flow in the process is accurately defined. Fluid velocity measurements are important for fluid flow quality performance in flow systems. This study focuses on determination of the volumetric flow rate and its standard (relative) deviation for calibration of conventional flow meters by using a radiotracer approach. The measurements for flow meter calibration were performed at a pilot-scale flow rig using Technetium-99 m (99mTc) as a radiotracer in the form of pertechnetate ion (99mTcO4-). The measured data were analyzed, and precision of the experimental setup was investigated under two different approaches ? IAEA?s RTD software and sum approximation of raw data. For the first time, the variation of standard deviation of calculated flow rate with the injection volume and activity of the radiotracer was determined. Plug flow with axial dispersion was used to simulate the measured RTD curves and investigate the flow dynamics of the flowing water. The results of the study have shown the possibility of in situ calibration of flow meters with a relative error lower than 1 %. They also revealed a slight dependency of the precision of output results on the injection volume as well as similar results for manual and specialized RTD software data processing.

Comprehensive analysis of the thermohydraulic performance of cooling networks subject to fouling and undergoing retrofit projects

2020 ◽  
pp. 0958305X2094531
Author(s):  
Hebert Lugo-Granados ◽  
Lázaro Canizalez-Dávalos ◽  
Martín Picón-Núñez
Keyword(s):  
Pressure Drop ◽  
Water Flow ◽  
Flow Rate ◽  
Fluid Velocity ◽  
Water Flow Rate ◽  
Volumetric Flow Rate ◽  
Cooling Capacity ◽  
Point Of View ◽  
Rate Distribution

The aim of this paper is to develop guidelines for the placing of new coolers in cooling systems subject to retrofit. The effects of the accumulation of scale on the flow system are considered. A methodology to assess the interconnected effect of local fluid velocity and fouling deposition is developed. The local average fluid velocity depends on the water flow rate distribution across the piping network. The methodology has four main calculation components: a) the determination of the flow rate distribution across the piping network, b) the prediction of fouling deposition, c) determination of the hydraulic changes and the effect on fouling brought about by the placing of new exchangers into an existing structure, and d) the calculation of the total cooling load and pressure drop of the system. The set of disturbances introduced to the system through fouling and the incorporation of new coolers, create network responses that eventually influence the cooling capacity and the pressure drop. In this work, these interactions are analysed using two case studies. The results indicate that, from the thermal point of view, the incorporation of new heat exchangers is recommended in series. The limit is the point where the increase of the total pressure drop causes a reduction in the overall volumetric flow rate. New coolers added in parallel create a reduction of pressure drop and an increase in the overall water flow rate; however, this increase is not enough to counteract the reduction of fluid velocity and heat capacity removal.

scholarly journals Volumetric flow rate in simulations of microfluidic devices

2018 ◽  
Vol 180 ◽  
pp. 02046
Author(s):  
KristÍna Kovalčíková ◽  
Martin Slavík ◽  
Katarína Bachratá ◽  
Hynek Bachratý ◽  
Alžbeta Bohiniková
Keyword(s):  
External Force ◽  
Flow Rate ◽  
Laboratory Experiments ◽  
Fluid Velocity ◽  
Volumetric Flow Rate ◽  
Microfluidic Devices ◽  
Fixed Set ◽  
Volumetric Rate ◽  
Simulation Parameter ◽  
Set Up

In this work, we examine the volumetric flow rate of microfluidic devices. The volumetric flow rate is a parameter which is necessary to correctly set up a simulation of a real device and to check the conformity of a simulation and a laboratory experiments [1]. Instead of defining the volumetric rate at the beginning as a simulation parameter, a parameter of external force is set. The proposed hypothesis is that for a fixed set of other parameters (topology, viscosity of the liquid, …) the volumetric flow rate is linearly dependent on external force in typical ranges of fluid velocity used in our simulations. To confirm this linearity hypothesis and to find numerical limits of this approach, we test several values of the external force parameter. The tests are designed for three different topologies of simulation box and for various haematocrits. The topologies of the microfluidic devices are inspired by existing laboratory experiments [3 - 6]. The linear relationship between the external force and the volumetric flow rate is verified in orders of magnitudes similar to the values obtained from laboratory experiments.

Fabrication of Microfluidic Rapid Micromixer

2011 ◽  
Vol 467-469 ◽  
pp. 2013-2017
Author(s):  
Hsiang Chen Hsu ◽  
Hsi Chien Liu ◽  
Cheng Jiun Han
Keyword(s):  
Flow Rate ◽  
Fluid Velocity ◽  
Volumetric Flow Rate ◽  
Mixing Efficiency ◽  
Mixing Index ◽  
Micro Pump ◽  
Chaotic Convection ◽  
Wide Range ◽  
Parametric Studies ◽  
Junction Type

A microfluidic multi-cylindric rapid micromixer is fabricated in the present paper. The key features in the presented MEMS-based microchannel design are (1) micro pump (2) Y-junction type channel (3) cylindric obstacle (4) notch with the edge of sharp teeth. Two different fluids (DI water and red ink) were pumped and injected into Y-type channel, and the fluids were broken-up by a cylindric obstacle in the center of tapered microchannel. The chaotic convection occurs in the mixing channel behind the cylindric obstacle. The mixing index is defined to qualify the mixing efficiency, which demonstrates the outlet notch with sharp teeth along the sidewall plays an important role for mixing effects. The developed micromixer can enhance mixing using the mechanisms of diffusion and convection for wide range of Reynolds number (0.01<Re<100). Parametric studies for volumetric flow rate include the number of cylindric obstacles, the number of notches with sharp-teeth and the width of microchannel. Preliminary results demonstrate that the mixing index reaches the desired effect (<0.1) within 0.08 second when the inlet fluid velocity is 0.49992m/s, i.e. volumetric flow rate is 1200μl /min. The presented device is faster than most of reported micromixers.

scholarly journals Assessing the degree of plug flow in oxidation flow reactors (OFRs): a study on a potential aerosol mass (PAM) reactor

2018 ◽  
Vol 11 (3) ◽  
pp. 1741-1756 ◽  
Author(s):  
Dhruv Mitroo ◽  
Yujian Sun ◽  
Daniel P. Combest ◽  
Purushottam Kumar ◽  
Brent J. Williams
Keyword(s):  
Flow Rate ◽  
Cfd Simulation ◽  
Plug Flow ◽  
Volumetric Flow Rate ◽  
Flow Patterns ◽  
Space Time ◽  
Flow Reactors ◽  
Tracer Testing ◽  
Aerosol Mass ◽  
In Series

Abstract. Oxidation flow reactors (OFRs) have been developed to achieve high degrees of oxidant exposures over relatively short space times (defined as the ratio of reactor volume to the volumetric flow rate). While, due to their increased use, attention has been paid to their ability to replicate realistic tropospheric reactions by modeling the chemistry inside the reactor, there is a desire to customize flow patterns. This work demonstrates the importance of decoupling tracer signal of the reactor from that of the tubing when experimentally obtaining these flow patterns. We modeled the residence time distributions (RTDs) inside the Washington University Potential Aerosol Mass (WU-PAM) reactor, an OFR, for a simple set of configurations by applying the tank-in-series (TIS) model, a one-parameter model, to a deconvolution algorithm. The value of the parameter, N, is close to unity for every case except one having the highest space time. Combined, the results suggest that volumetric flow rate affects mixing patterns more than use of our internals. We selected results from the simplest case, at 78 s space time with one inlet and one outlet, absent of baffles and spargers, and compared the experimental F curve to that of a computational fluid dynamics (CFD) simulation. The F curves, which represent the cumulative time spent in the reactor by flowing material, match reasonably well. We value that the use of a small aspect ratio reactor such as the WU-PAM reduces wall interactions; however sudden apertures introduce disturbances in the flow, and suggest applying the methodology of tracer testing described in this work to investigate RTDs in OFRs to observe the effect of modified inlets, outlets and use of internals prior to application (e.g., field deployment vs. laboratory study).

scholarly journals Sensor Based Leakage Detection in Vacuum Bagging

2021 ◽  
Author(s):  
Anja Haschenburger ◽  
Niklas Menke ◽  
Jan Stüve
Keyword(s):  
Flow Rate ◽  
Air Flow ◽  
Volumetric Flow Rate ◽  
Detection Methods ◽  
Industrial Processes ◽  
Special Focus ◽  
Leakage Detection ◽  
Flow Meters ◽  
New Approach

Abstract The majority of aircraft components are nowadays manufactured using autoclave processing. Essential for the quality of the component is the realization of an air tight vacuum bag on top of the component to be cured. Several ways of leakage detection methods are actually used in industrial processes. They will be dealt with in this paper. A special focus is put on a new approach using flow meters for monitoring the air flow during evacuation and curing. This approach has been successfully validated in different trials, which are presented and discussed. The main benefit of the method is that in case of a leakage, a defined limit is exceeded by the volumetric flow rate whose magnitude can be directly correlated to the leakage’s size and position. In addition the potential of this method for the localization of leakages has been investigated and is discussed.

scholarly journals Simulating Trambouze reaction for a series reactor

2020 ◽  
Vol 3 (1) ◽  
pp. 1
Author(s):  
Amizon Azizan ◽  
Nornizar Anuar
Keyword(s):  
Flow Rate ◽  
Coming Out ◽  
Flow Reactor ◽  
Plug Flow ◽  
Volumetric Flow Rate ◽  
Continuous Stirred Tank Reactor ◽  
Maximum Conversion ◽  
Outlet Stream ◽  
Continuous Stirred Tank ◽  
Flow Rate Influence

Simulating the existing data on Trambouze reaction is compiled in this article. The objective of the work is to present the change of volumetric flow rate and the inlet concentration of key reactant A in a series continuous stirred tank reactor-plug flow reactor (CSTR-PFR) configurations. The volumetric flow rate does not affect selectivity and conversion for a constant volumetric flow rate operating condition, entering CSTR and PFR, at a specific concentration of reactant. The CSTR-PFR series reactor configuration is proposed for the aim of maximizing the selectivity of the desired product B in comparison to the undesired products X and Y. CSTR as the first reactor is capable to achieve the maximum conversion at the highest selectivity of A. PFR is then proposed after CSTR in a configuration of CSTR-PFR, to allow higher conversion value to be achieved for the resulted outlet stream conditions coming out of the first reactor, CSTR. Both reactors commonly encounter a decrease in the initial concentration of A and an increase to the formation of other products. The CSTR entering volumetric flow rate influence the volume sizes needed in achieving the maximum selectivity and conversion

scholarly journals Effect of magnetic field on Newtonian fluid sandwiched between non-Newtonian fluids through porous cylindrical shells

2021 ◽  
Author(s):  
Deepak Kumar Maurya ◽  
Satya Deo
Keyword(s):  
Magnetic Field ◽  
Newtonian Fluid ◽  
Flow Rate ◽  
Hartmann Number ◽  
Viscosity Ratio ◽  
Fluid Velocity ◽  
Fluid Motion ◽  
Volumetric Flow Rate ◽  
Shear Stresses ◽  
Micropolar Fluids

Abstract The present work deals with the influence of magnetic field on Newtonian fluid sandwiched between two porous cylindrical pipes which are filled with micropolar fluids. Fluid motion is occurring along z*-axis and applied magnetic field is taken in the direction perpendicular to the direction of fluid motion. On applying appropriate boundary conditions, velocity profiles, microrotations, flow rate and shear stresses are obtained for the corresponding fluid regions. The graphs for volumetric flow rate and fluid velocity are plotted and discussed for different values of micropolar parameter, couple stress parameter, porosity, viscosity ratio parameter, Hartmann number, conductivity ratio parameters and Darcy numbers.MSC (2020): 76A05, 76S05, 76W05, 35Q35

scholarly journals Sensor-based leakage detection in vacuum bagging

2021 ◽  
Author(s):  
Anja Haschenburger ◽  
Niklas Menke ◽  
Jan Stüve
Keyword(s):  
Flow Rate ◽  
Air Flow ◽  
Volumetric Flow Rate ◽  
Detection Methods ◽  
Industrial Processes ◽  
Special Focus ◽  
Leakage Detection ◽  
Flow Meters ◽  
New Approach

AbstractA majority of aircraft components are nowadays manufactured using autoclave processing. Essential for the quality of the component is the realization of an airtight vacuum bag on top of the component to be cured. Several ways of leakage detection methods are actually used in industrial processes. They will be dealt with in this paper. A special focus is put on a new approach using flow meters for monitoring the air flow during evacuation and curing. This approach has been successfully validated in different trials, which are presented and discussed. The main benefit of the method is that in case of a leakage, a defined limit is exceeded by the volumetric flow rate whose magnitude can be directly correlated to the leakage’s size and position. In addition, the potential of this method for the localization of leakages has been investigated and is discussed.

The pumping characteristics of screw rotors. I. The theory of calculation of the pumping capacity of screw rotors

1987 ◽  
Vol 52 (2) ◽  
pp. 357-371 ◽  
Author(s):  
František Rieger
Keyword(s):  
Present State ◽  
Flow Rate ◽  
Volumetric Flow Rate ◽  
Screw Rotor ◽  
Screw Rotors

This paper summarizes the present state of the theory of calculation of the pumping capacity of screw rotors. The calculation starts from the equation for the volumetric flow rate of the flow between two unconfined plates modified by correction coefficients obtained from the relationships for the flow rate in simpler geometrical configurations to which the screw rotor may be, under certain circumstances, reduced.

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