Determination Of Mass Flow Research Articles

Sensitivity analysis of heat flow of heat exchangers in ethanol-water distillation column

In this study sensitivity analysis was made with Unisim Design process simulator software for ethanol-water mixture. The effect of the reflux ratio and the number of trays on the heat flow of the heat exchangers was investigated in case of different purification of bottom product. The results of the sensitivity analysis showed that the heat flow of the reboiler averagely 1.94 times higher than the heat flow of the condenser. Afterwards, the effect of the thermal state of the feed stream was investigated on the heat flow of the condenser and the reboiler. In each cases the mass flow and ethanol content of the distillate stream were also investigated. The results showed that in the studied cases the liquid volume percent of the ethanol varies between 65% and 87%. A simplified cost estimation was calculated with the determination of mass flow of cooling water and low-pressure steam. From the results it was concluded that higher number of trays, higher temperature of the feed stream and higher ethanol content in the bottom product resulted lower costs of the utility streams.

Particle mass flow determination in dust-laden supersonic flows by means of simultaneous application of optical measurement techniques

Particle mass flow rate and particle mass concentration are key parameters for describing two-phase flows, especially for particle-induced heating augmentation analysis. This work addresses the question of how accurate particle mass flow rate can be determined with three non-intrusive measurement approaches, based on shadowgraphy, particle tracking velocimetry (PTV), and scattered light intensity, in supersonic flows. In terms of shadowgraphy and PTV, the particle mass flow rate was determined by measuring individual particle characteristics, namely particle size, velocity, and density, as well as the measurement volume. The presented shadowgraphy procedure is based on the commercial LaVision DaVis software and additional shadowgraphy corrections. Multiple tests were conducted in the experimental test facility GBK of DLR with varying flow conditions, at a Mach number of 2.1, unit Reynolds number (Re∞) ranging from 5e7 1/m to 1.5e8 1/m, total temperature (T0) ranging from 303 to 544 K, and particle materials, namely Al2O3, MgO, and SiO2, in the size range of 1 to 60 µm. Particle size distributions of Al2O3 and MgO particles could be reproduced with shadowgraphy quite well, while the PTV procedure resulted in non-similar distributions. Pycnometer measurements indicated MgO particle density to be significantly lower than reference values. A DaVis parameter variation analysis resulted in a particle mass flow rate uncertainty of shadowgraphy of up to 30%. The particle mass flow rate uncertainty of PTV is approx. 76%, and the respective uncertainty of scaled PTV and scattered light intensity approach is 28%. The particle mass flow rate, measured with shadowgraphy, is 58% higher than those of the semi-axisymmetric scattered light intensity approach, which can be explained by a higher particle concentration at the injection plane.

Simultaneous determination of particle size, velocity, and mass flow in dust-laden supersonic flows

The particle mass concentration and -mass flow rate are fundamental parameters for describing two-phase flows and are products of particle number, -size, -velocity, and -density. When investigating particle-induced heating augmentation, a detailed knowledge of these parameters is essential. In most of previous experimental studies considering particle-induced heating augmentation, only average particle mass flow rates are given, without any relation to measured particle sizes and -velocities within the flow or any indication of measurement uncertainty. In this work, particle number, individual particle sizes, and velocities were measured in a supersonic flow by means of shadowgraphy and particle tracking velocimetry (PTV). The goals are to determine measurement uncertainties, a particle velocity-size relation, and the spatial distribution of number, size, velocity, and mass flow rate across the nozzle exit. Experiments were conducted in a facility with a nozzle exit diameter of 30 mm, at Ma∞ = 2.1 and Re∞ = 8.2e7 1/m. Particles made of Al2O3 and up to 60 µm in size were used for seeding. Particle mass flow rates up to 50 kg/m2 s were achieved. It is shown that an additional correction procedure reduced common software uncertainties regarding shadowgraphy particle size determination from 14% to less than 6%. Discrepancies between calculated particle velocities and experimental data were found. In terms of spatial distribution, larger particles and a higher mass flow rate concentrate in the flow center. The determined particle mass flow rate uncertainty was up to 50% for PTV; for shadowgraphy, it was less than 17%.Graphical abstract

A Semi-Empirical Fluid Dynamic Model of a Vacuum Microgripper Based on CFD Analysis

Vacuum microgrippers are devices used to handle and manipulate small objects. Despite their simple working principle and low cost, they show low efficiency in detaching performance, especially when the object to be grasped is very small. In this work, a particular design for vacuum microgrippers with an incorporated automatic release tool is considered. The final goal of this study was to present a numerical model that can supply reliable estimates of the aerodynamic force acting on the release tool and of the air flow rate inside the gripper as a function of geometric parameters and the outlet pressure value. A complete CFD analysis of a simplified model of the device is presented. Grid independence analysis was also performed to define a suitable grid and guarantee a good trade-off between accuracy and computing time. According to Design of Experiments (DOE) techniques, 81 simulations were performed, changing the values of the outlet pressure (p2), the body inner diameter (D), the lateral holes’ diameter (d) and the releasing mass length (L). Every design variable could assume three different values. Linear regression, based on the least square method, was employed to determine mass flow rate and lifting force empirical correlations.

Exhaust Gas Mass Flow Determination on the Highly Dynamic Motorcycle Test Bench with PEMS

Exhaust Gas Mass Flow Determination on the Highly Dynamic Motorcycle Test Bench with PEMS

Design Analysis and performance evaluation of 3D printed baffle path diverters in hydraulic noise suppressor

The pump in the hydraulic systems is the main source of noise in form of vibrations or pulsations while noise reduction is an important part of pump design still some ripples are produced by the pump termed as pulsations. Pulsations result in line vibrations which cause additional noise. How much ripple the pump produces cannot be changed, so other ways to an average of 50 dB(A) to 60 dB(A) level of noise is often considered to safe, although the noise levels resulting due to pulsations are seen to be in ranges as high as 130 t 0 150 dB(A) that result in hose and piping failures and also results in damage to components like seals and valves. Through the introduction of a compressible membrane in the path with additional baffles for muffling of the noise the proposed solution is in the form of hydraulic noise reducer that incorporates both the compressible membrane as well as the baffle path diverter. Objective of paper is carried out the performance evaluation of the hydraulic noise reducer with elastomer membrane for noise reduction mechanism in conjunction to baffle type path diverters to even out the fluid pulsations or ripple to minimal without much pressure drop across the device to achieve minim; pumping losses. The paper discusses the performance evaluation of the diverter. The has been tested to determine mass flow rate and pressure drop. Experimental has been manufactured and test has been conducted to evaluate reduction in noiselevelinwithandwithoutthe3-dprintedbaffle arrangement and comparison has been carried out.

Numerical Simulation of Emergency Release of Liquid Petroleum Gas on a Car Gas Station

LPG storage tanks may be seriously threatened by a fire coming from nearby fuels or by leakage appearance. The aim of the study was to prepare a three-dimensional model of LPG release on a car gas station under different environmental conditions. CFD simulations of liquid and gas phase release from a tank localized on a car gas station was performed. First, ALOHA software was applied to determine mass flow rate, while Ansys software was used to determine the shape and size of hazardous zone. To reflect real condition atmospheric stability classes were applied. It was observed that for classes A-D the hazardous zone was decreasing. While, for E and F class the range was increased. It was noticed that the location of the leakage affects the extent of the danger zone. For the leaking below the liquid surface analyzed LPG has liquid form. While, for the leaking above the liquid surface analyzed LPG has gas form. Furthermore, for liquid leakage the largest hazard zone of release was observed.

Permeability determination in tight rock sample using novel method based on partial slip modelling and X-ray tomography data

Purpose The purpose of the paper was the application of computational fluid dynamics (CFD) techniques in fluid flow using Maxwell’s equation for partial slip modelling, estimating the flow parameters, and selecting tangential momentum accommodation coefficient (TMAC) for tight rock samples in permeability calculations. Design/methodology/approach The paper presents a numerical analysis of fluid flow in a low-porosity rock sample by using CFD. Modelling results allowed to determine mass flow rates in a rock sample and to calculate permeability values using a modified Darcy’s equation. Three-dimensional (3D) geometrical model of rock sample generated using computed X-ray tomography was used in the analysis. Steady-state calculations were carried out for defined boundary conditions in the form of pressure drop. The simulations were applied taking into account the slip phenomenon described by Maxwell’s slip model and TMAC. Findings Values of permeability were calculated for different values of TMAC, which vary from 0 to 1. Results in the form of gas mass flow rates were compared with the measured value of permeability for rock sample, which confirmed the high accuracy of the presented model. Practical implications Calculations of fluid flow in porous media using CFD can be used to determine rock samples’ permeability. In slip flow regime, Maxwell’s slip model can be applied and the empirical value of TMAC can be properly estimated. Originality/value This paper presents the usage of CFD, Maxwell’s equation for partial slip modelling, in fluid flow mechanism for tight rock samples. 3D geometric models were generated using created pre-processor (poROSE software) and applied in the raw form for simulation.

Криволинейное радиальное течение сжимаемой вязкопластичной нефти со свободной текучестью в однородном пласте

The paper presents a solution to a steady-state hydrodynamic problem dealing with one-dimensional free-surface radial flow of compressible viscoplastic oil in a horizontal homogeneous circular formation. A vertical producing oil well is located in the centre of the formation, penetrating the pay zone fully, with no well casing or perforation present. We used generalised Darcy's law and equations of state for a compressible fluid to determine mass flow rate of the compressible viscoelastic oil and derive equations for current density, oil flow rate, current pressure distribution in the drainage area, and current pressure gradient. The equations take into account oil compressibility and initial pressure gradient. We also determined the time it takes an oil particle to reach the well starting from the current radius vector and from the external boundary. This is the case when the oil deposit lies close to the earth surface. This depth range features no shale beds or interbedded formations. Since subsurface mining is possible with shallow oil deposits, both wells and tunnels may be used for production.

Inline gas/liquid flow measurement using sequential static mixing elements

This work explores the use of two sequential static mixers for the determination of mass flow and density of an effervescent two-phase mixture where compressibility effects remain relevant. The upstream static mixer exhibited a non-standard two-phase pressure drop correction factor (KL) due to flow homogenization dynamics, while the downstream static mixer exhibited more traditional KL vs. gas fraction trends. Through combination of the two mixers, mass flow rate was estimated to within ± 5 kg/h for the majority of conditions up to 100 kg/h and 70% gas fraction. Density estimates were comparable to those obtained from an in-line commercial Coriolis meter, with relative error consistently within ± 100 kg/m3 of actual bulk-phase densities. The configuration resulted in predictions comparable to an inline commercial Coriolis meter over a broad range of flow conditions, and represents a relatively inexpensive flow metering approach provided sufficient gas expansion is achieved to cause a variation in KL. Topic points•Use of sequential static mixers to normalize flow patterns in gas-liquid systems.•Introduction of a sudden expansion to induce gas fraction variation and a corresponding change in the 2-phase flow modifier, KL.•Comparison of calibrated results to a commercial Coriolis meter.

Generalization of the algorithm of determining mass flow rate by measuring pressure in gas transportation systems

The current algorithm for calculating mass flow rate in gas production and transportation systems via outlet pressure measurements is generalized to the case when the inner cross section of pipe changes with time and is also to be determined while solving the general problem. The algorithm is recommended for identification of gas hydrate formation in the above-mentioned systems.

Quantitative Bioimaging of Platinum via Online Isotope Dilution-Laser Ablation-Inductively Coupled Plasma Mass Spectrometry.

A new calibration strategy for elemental bioimaging based on online isotope dilution analysis (IDA) and laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS) was developed and applied for the quantification of platinum in rat kidney tissues. A dry 194Pt spike aerosol was added in a post-cell setup, and the natural 194Pt/195Pt isotope ratio of the sample aerosol from laser ablation was changed accordingly. Spike mass flow determination was carried out based on reversed IDA using a reference standard. Quantitative data obtained by the new approach correlated well with those obtained by external calibration when analyzing parallel tissue slices of rat kidney from cisplatin perfusion studies. The novel quantification approach is traceable to SI units, as IDA is an definitive method. Signal drifts are compensated as the second isotope acts as an internal standard.

Volumetric efficiency modelling of internal combustion engines based on a novel adaptive learning algorithm of artificial neural networks

Air mass flow determination is one of the main variables on the control of internal combustion engines. Effectiveness of intake air systems is evaluated through the volumetric efficiency coefficient. Intake air systems characterization by means of physical models needs either significant amount of input data or notable calculation times. Because of these drawbacks, empirical approaches are often used by means of black-box models based on Artificial Neural Networks. As alternative to the standard gradient descendent method an adaptive learning algorithm is developed based on the increase of hidden layer weight update speed. The results presented in this paper show that the proposed adaptive learning method performs with higher learning speed, reduced computational resources and lower network complexities. A parametric study of several Multiple Layer Perceptron (MLP) networks is carried out with the variation of the number of epochs, number of hidden neurons, momentum coefficient and learning algorithm. The training and validation data are obtained from steady state tests carried out in an automotive turbocharged diesel engine.

Analysis of influence of mechanical boundary conditions on zero point shift of Coriolis flowmeter

Coriolis flow meters determine mass flow rate by measuring the phase shift of the signal pick-up coils. Therefore, changes in the phase shift amount not related to the flow of the measured medium cause mass flow measurement errors. The article is devoted to the experimental evaluation of the effect of mechanical boundary conditions of the Coriolis flowmeter on zero point shift. Special equipment, allowing changing the stiffness of the pipeline, to which the flowmeter is attached, has been developed. Modal experiments on the Coriolis flowmeter without liquid for different lengths of pipe have been conducted. It has been found out that the maximum zero point shift is observed when the frequency of natural vibrations of the coupled system of the flow meter and piping tubes coincides with the drive frequency of tube vibrations. Tests to assess the influence of external vibration on the zero point shift have been conducted. The maximum zero point shift is observed in the coincidence of the external vibration frequency with the drive frequency of oscillation of tubes.

Анализ влияния условий закрепления на смещение нуля кориолисого расходомера

A Coriolis flowmeter is used for measuring mass flow of liquids and gases. The Coriolis flow meters determine mass flow rate by measuring the phase shift of the U-shaped vibrating tubes. The tubes make forced oscillations at the resonance frequency. It is drive frequency. The phase shift is proportional to the mass flow. Therefore, changes in the phase shift amount not related to the flow of the measured medium, leadto mass flow measurement error. The article is devoted to the experimental evaluation of the effect of mechanical boundary conditions of the Coriolis flowmeter on zero point shift. The zero point shift of the Coriolis flow meter is the value of the phase difference without the flow of the medium. A special equipment, allowing to change the stiffness of the pipeline, to which the flowmeter is attached, has been developed. There have been conducted modal experiments on the Coriolis flowmeter with liquid for different lengths of pipe. Changing the length of the tubing affects the modes of the coupled flowmeter-piping system. The tests were carried out on a flowmeter with tubes filled with water without flow and with a flow of water with a constant flow rate. It has been found out that the maximum zero point shift is observed when the frequency of natural vibrations of the coupled system of the flow meter and piping tubes coincides with the drive frequency of tube vibrations. In the article the additional fixation of the flowmeter for the case. To reduce the modes affecting the zero point shift.

Количественное определение массового расхода веществ, находящихся в составе топлива и материалах конструкции ракетных двигателей, способом спектральной диагностики при огневых испытаниях

Количественное определение массового расхода веществ, находящихся в составе топлива и материалах конструкции ракетных двигателей, способом спектральной диагностики при огневых испытаниях

A mmWave Measuring Procedure for Mass Flow Monitoring of Pneumatic Conveyed Bulk Materials

In this contribution a novel measuring concept for mass flow determination of pneumatic conveyed particles is presented. Therefore, the so-called pseudo transmission measurement concept was adapted for the simultaneous determination of volume fraction and particle flow velocity within a pneumatic conveying tube. The application of two ultra wideband 80-GHz FMCW radar systems increases the measuring accuracy and is used for measurements on a continuous particle flow. Therefore, an experimental pneumatic conveying system is introduced. Flow simulations of the conveying pipe and 3-D electromagnetic simulations of the measurement method illustrate the flow behavior inside the conveying tube and the RF-measuring performance, respectively. Measurement results concerning the volume fraction determination as well as the velocity determination will be presented and discussed in detail.

Smoke and heat flow in a large volume building in case of fire

In the paper author presents chosen analytic formulas for determining mass flow of heat and smoke into smoke reservoir in prescribed layout of vertical and horizontal wall boundaries, which include room where the fire starts, a wall with an opening and a downstand, and a projecting balcony, all fit inside a large volume building. Results of analytical calculations were compared to the results of performed numerical studies using CFD method, and the final design guidelines are given.

New emissions targeting strategy for site utility of process industries

A new procedure for environmental targeting of co-generation system is presented. The proposed method is based on the concepts of pinch technology for total site targeting of fuel, power, steam, environmental impacts and total annualized cost with considering emissions taxes. This approach provides a consistent, general procedure for determining mass flow rates and efficiencies of the applied turbines. This algorithm utilizes the relationship of entropy with enthalpy and isentropic efficiency. Also, the life cycle assessment (LCA) as a well-known tool for analyzing environmental impacts on a wide perspective with reference to a product system and the related environmental and economic impacts have been applied. In this regard, a damage-oriented impact analysis method based on Eco-indicator 99 and footprints analysis was considered. In addition, the present work demonstrates the effect of including both sensible and latent heating of steam in the extended Site Utility Grand Composite Curve (ESUGCC). It is shown that including sensible heating allows for better thermal matching between the processes. Furthermore, the other representation YSUGCC as the other form of Site Utility Grand Composite has been proposed. Two case studies were used to illustrate the usefulness of the new environmental targeting method.

Experimental Test Results for a Fiber Bragg Grating-based Flow Sensor

A fiber optic-based mass flow sensor has been developed that uses fiber Bragg gratings to deduce flow velocity. Flow velocity, local temperature, pressure measurements (which all can be extracted using fiber Bragg gratings), and geometric information can be combined to determine mass flow. A range of concepts have each been investigated and compared using the same “design of experiment” for each sensor. The most promising concept has been further developed into a prototype. The working prototype successfully demonstrated a thermally insensitive sensor design that has the capability to track flow velocities. The sensor design is incorporated directly with a structural beam element to magnify the strain effect while simultaneously compensating for thermally induced wavelength shifts in the sensor response. Further testing has been performed using three flexible beams at different angular positions, demonstrating that flow angles can be measured using a similar approach to that used for three-hole pneumatic probes. As a final test, the sensor has been tested in a shock tube, demonstrating superior performance to steady pneumatic measurements, which rely on tubing to reach the measurement location.