Research on the Vortex Mass Flow Meter of Dual Bluff Body Based on Differential Pressure Principle

2013 ◽  
Vol 401-403 ◽  
pp. 1110-1113
Author(s):  
Quan Sheng Duan ◽  
Li Cui Wang
Keyword(s):  
Lower Limit ◽  
Mass Flow ◽  
Flow Rate ◽  
Bluff Body ◽  
Differential Pressure ◽  
Low Flow ◽  
Body Structure ◽  
Measurement Sensitivity ◽  
Flow Meter ◽  
Pressure Signal

The lower limit of the existing vortex mass flow meter based on differential pressure is high. So the application of the existing vortex mass flow meter is limited in the measurement for low flow rate. This paper proposes a method using vortex mass flow meter of dual bluff body based on differential pressure principle. The differential pressure signal between the upstream and downstream can be amplified by the vortex overlap caused by the dual bluff body structure. The results of the simulation by Fluent show that this method can reduce the lower limit of measurement, and improve the measurement sensitivity effectively.

scholarly journals Backflow effects on mass flow gain factor in a centrifugal pump

2021 ◽  
Vol 104 (2) ◽  
pp. 003685042199886
Author(s):  
Wenzhe Kang ◽  
Lingjiu Zhou ◽  
Dianhai Liu ◽  
Zhengwei Wang
Keyword(s):  
Centrifugal Pump ◽  
Mass Flow ◽  
Flow Rate ◽  
Low Frequency ◽  
Gain Factor ◽  
Low Flow ◽  
Cavity Volume ◽  
Cavitating Flows ◽  
Inlet Tube ◽  
Low Flow Rate

Previous researches has shown that inlet backflow may occur in a centrifugal pump when running at low-flow-rate conditions and have nonnegligible effects on cavitation behaviors (e.g. mass flow gain factor) and cavitation stability (e.g. cavitation surge). To analyze the influences of backflow in impeller inlet, comparative studies of cavitating flows are carried out for two typical centrifugal pumps. A series of computational fluid dynamics (CFD) simulations were carried out for the cavitating flows in two pumps, based on the RANS (Reynolds-Averaged Naiver-Stokes) solver with the turbulence model of k- ω shear stress transport and homogeneous multiphase model. The cavity volume in Pump A (with less reversed flow in impeller inlet) decreases with the decreasing of flow rate, while the cavity volume in Pump B (with obvious inlet backflow) reach the minimum values at δ = 0.1285 and then increase as the flow rate decreases. For Pump A, the mass flow gain factors are negative and the absolute values increase with the decrease of cavitation number for all calculation conditions. For Pump B, the mass flow gain factors are negative for most conditions but positive for some conditions with low flow rate coefficients and low cavitation numbers, reaching the minimum value at condition of σ = 0.151 for most cases. The development of backflow in impeller inlet is found to be the essential reason for the great differences. For Pump B, the strong shearing between backflow and main flow lead to the cavitation in inlet tube. The cavity volume in the impeller decreases while that in the inlet tube increases with the decreasing of flow rate, which make the total cavity volume reaches the minimum value at δ = 0.1285 and then the mass flow gain factor become positive. Through the transient calculations for cavitating flows in two pumps, low-frequency fluctuations of pressure and flow rate are found in Pump B at some off-designed conditions (e.g. δ = 0.107, σ = 0.195). The relations among inlet pressure, inlet flow rate, cavity volume, and backflow are analyzed in detail to understand the periodic evolution of low-frequency fluctuations. Backflow is found to be the main reason which cause the positive value of mass flow gain factor at low-flow-rate conditions. Through the transient simulations of cavitating flow, backflow is considered as an important aspect closely related to the hydraulic stability of cavitating pumping system.

Using an Adjustable Cone Meter to Measure Wet Gas

2021 ◽  
Author(s):  
Sakethraman Mahalingam ◽  
Gavin Munro ◽  
Muhammad Arsalan ◽  
Victor Gawski
Keyword(s):  
Flow Rate ◽  
Pressure Measurement ◽  
Gas Flow ◽  
Flow Line ◽  
Liquid Fraction ◽  
Differential Pressure ◽  
Low Flow ◽  
Liquid Density ◽  
Estimation Model ◽  
Wet Gas

Abstract When the gas flow rate of a well significantly changes, the flow rate can fall below that of the operating range of a traditional fixed size Venturi meter, necessitating the replacement of the original meter with one of a smaller size. However, with an adjustable cone meter, the internal reconfiguration feature allows it to automatically switch from high operating flow range to low operating flow range and there is no requirement to disassemble the meter from the flow line assembly. Adjustable cone meters were designed, developed and tested at the wet-gas flow loop at National Engineering Laboratory in East Kilbride, Scotland. After calibrating the meter with dry nitrogen gas, the meter was tested with increasing amounts of liquid being injected into the flowline, upstream of the meter. The liquid caused the differential pressure measurement on the meter to over-read. Based on the differential pressure measurements under varying flow conditions, algorithms were developed to measure the dry gas and liquid fraction. The data obtained from the tests such as differential pressure, pressure, temperature, liquid density were used to build an over-reading model of the meter and a liquid fraction estimation model based on pressure loss ratio derived from an additional differential pressure measurement. The model was used to not only to quantify the gas and liquid flow rates but also the estimated error in each measurement. The measurements show that the Adjustable Cone meter is able to provide low uncertainty in both dry and wet gas conditions and offers a turndown ratio of up to 54:1 in dry gas conditions. In addition, the automatic adjustment of the meter from high flow to low flow positions avoids the need for manual intervention that involves additional risk and cost.

Experimental Investigation of Fuel Staging Effect on Modal Dynamics of Thermoacoustic Azimuthal Instabilities in a Multi-Nozzle Can Combustor

2021 ◽  
Author(s):  
J. Kim ◽  
W. Gillman ◽  
T. John ◽  
S. Adhikari ◽  
D. Wu ◽  
...  
Keyword(s):  
Standing Wave ◽  
Phase Difference ◽  
Mass Flow ◽  
Flow Rate ◽  
Oscillatory Behavior ◽  
Operating Conditions ◽  
Low Flow ◽  
Azimuthal Mode ◽  
Fuel Staging ◽  
Modal Dynamics

Abstract This paper analyzes the dynamics of unstable azimuthal thermoacoustic modes in a lean premixed combustor. Azimuthal modes can be decomposed into two counter rotating waves where they can either compete and potentially suppress one of them (spinning) or coexist (standing), depending on the operating conditions. This paper describes experimental results of the dynamical behaviors of these two waves. The experimental data were taken at different mass flow rates as well as different azimuthal fuel staging in a multi-nozzle can combustor. It is shown that at a low flow rate with uniform fuel distribution, the two waves have similar amplitudes, giving rise to a standing wave. However, the two amplitudes are slowly oscillating out of phase to each other, and the phase difference between the two waves also shows oscillatory behavior. For an intermediate flow rate, the dynamics show intermittency between standing and spinning waves, indicating that the system is bistable. In addition, the phase difference dramatically shifts when the mode switches between standing and spinning waves. For a high flow rate, the system stabilizes at a spinning wave most of the time. These experimental observations demonstrate that not only the amplitudes of two waves but also the phase difference plays an important role in the dynamics of azimuthal mode. For non-uniform azimuthal fuel staging, the modal dynamics exhibit only an oscillatory standing wave behavior regardless of the mass flow rate. Compared to the uniform fuel staging, however, the pressure magnitude is considerably reduced, which provides a potential strategy to mitigate and/or suppress the instabilities.

scholarly journals Performance Analysis of Z-Blade Reaction Type Turbine for Low-Head Low Flowrate Pico Hydro

2021 ◽  
Vol 85 (2) ◽  
pp. 51-65
Author(s):  
Mohd Farriz Basar ◽  
Fatin Syakira Mohd Hassan ◽  
Nurul Ashikin Rais ◽  
Izzatie Akmal Zulkarnain ◽  
Wan Azani Wan Mustafa
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Rotational Speed ◽  
Low Flow ◽  
Practical Case ◽  
Reaction Type ◽  
K Factor ◽  
Water Turbine ◽  
Low Head

The study explores the performance characteristics of a Z-Blade reaction type water turbine and investigates a test unit for an ideal and practical case using the governing equations derived from the principles of conservation of mass, momentum, and energy. Various analyses are conducted with consideration of the ideal and possible operating condition for low-head (3 m to 5 m) and low-flow (2.5 L/sec and below) water resources. The relationship of the fluid flow friction known as k-factor with mass flow rate and angular velocity for a Z-Blade turbine model is discussed. The measured performance of two PVC pipe sizes (0.5 inch and 1 inch) of a Z-Blade turbine is presented and evaluated against theoretical results. This work also describes the simple concept of a Z-Blade turbine for a pico-hydro application. A large variation in k-factor with a 1% difference in rotational speed and mass flow rate is presented. The coefficient k-factor is also demonstrated as a strong parameter influencing the mass flow rate and rotational speed performance. This coefficient also has a significant impact on the conversion of potential energy into power output.

Large Eddy Simulation of a Bluff-Body–Stabilized Flame With Close-Coupled Liquid Fuel Injection

2013 ◽  
Vol 136 (3) ◽  
Author(s):  
Andrew G. Smith ◽  
Suresh Menon ◽  
Jeffery A. Lovett ◽  
Baris A. Sen
Keyword(s):  
Mass Flow ◽  
Flow Rate ◽  
Liquid Fuel ◽  
Bluff Body ◽  
Fuel Flow Rate ◽  
Flow Rates ◽  
Fuel Mass ◽  
Fuel Flow ◽  
Large Eddy ◽  
Mass Flow Rates

Large eddy simulations (LES) are performed of a bluff-body–stabilized flame with discrete liquid fuel injectors located just upstream of the bluff-body trailing edge in a so-called “close-coupled” configuration. Nonreacting and reacting simulations of the Georgia Tech single flameholder test rig [Cross et al., 2010, “Dynamics of Non-premixed Bluff Body-Stabilized Flames in Heated Air Flow,” Proceedings of ASME Turbo Expo, Paper No. GT2010-23059] are conducted using an Eulerian–Lagrangian approach with a finite volume solver. Experimental data is first used to characterize the boundary conditions under nonreacting conditions before simulating reacting test cases at two different fuel mass flow rates. The two fuel mass flow rates not only result in different global equivalence ratios but different spatial distributions of fuel, especially in the near-field wake of the bluff body. The differing spatial distribution of fuel results in two distinct flame dynamics; at the high-fuel flow rate, large-scale sinusoidal Bérnard/von-Kármán (BVK) oscillations are observed, whereas a symmetric flame is seen under the low-fuel flow rate condition.

The Optimal Design of the New Tube Inside and Outside Differential Pressure Flow Meter

2014 ◽  
Vol 541-542 ◽  
pp. 1283-1287
Author(s):  
Shuang Wei Xie ◽  
Jing Zhe Gao ◽  
Zi Tong Wen ◽  
Li De Fang ◽  
Xiang Jie Kong ◽  
...  
Keyword(s):  
Optimal Design ◽  
Differential Pressure ◽  
Measuring Instrument ◽  
Flow Meter ◽  
Pressure Flow ◽  
Flow Meters ◽  
Application Range ◽  
Pressure Signal ◽  
Mechanical Structure ◽  
The Stability

Differential pressure flow meter is a kind of very promising flow measuring instrument, the application range is very wide. But aiming at the defects that the mechanical structure of all kinds of existing flow meters is complex, the throttling way disturbs the fluid greatly and the stability of differential pressure signal is insufficient, a kind of new inside and outside tube differential pressure flow meter was designed.

A By-Pass Sensor Package Design Enabling the Use of Microfluidics in High Flow Rate Applications

2006 ◽  
Author(s):  
D. Sparks ◽  
D. Goetzinger ◽  
D. Riley ◽  
N. Najafi
Keyword(s):  
Fuel Cell ◽  
Mass Flow ◽  
Flow Rate ◽  
Microelectromechanical Systems ◽  
High Flow ◽  
High Flow Rate ◽  
Low Flow ◽  
Package Design ◽  
Wide Range ◽  
Mems Device

The package design for microfluidic sensors is discussed. The MicroElectroMechanical Systems (MEMS) device covered in this paper requires a fluidic and electrical interface as well as vacuum packaging of the sensing element. By using a by-pass package design the limitations of low flow rate and high pressure drop often encountered with microfluidic products can be avoided. The MEMS device utilizes a resonating silicon microtube that is electrostatically driven and capacitively sensed. A platinum RTD is also integrated into the MEMS chip. To improve the Q of the resonator a thin-film getter has been integrated to lower the microcavity pressure. The microfluidic packaging technology lends itself to producing densitometers, chemical concentration meters and Coriolis mass flow sensors. The device has been applied to fuel cell concentration sensors for embedded Direct Methanol Fuel Cell (DMFC) systems. The DMFC systems require a methanol sensor to minimize crossover and hence optimize the water/methanol concentration over temperature and the life of the product. Other high flow rate applications include ethanol/gasoline concentration sensors for E85 vehicles and dialysis fluid monitoring. A microfluidic Coriolis mass flow sensor has been developed and applied to drug delivery to monitor the drug dose, total volume infused, drug type and concentration. Chemical and temperature compatibility of the MEMS chip and packaging materials must be considered when dealing with this wide range of applications and will be discussed in the paper.

scholarly journals Response of a Coriolis mass flow meter to step changes in flow rate

2003 ◽  
Vol 14 (3) ◽  
pp. 109-118 ◽  
Author(s):  
M.P. Henry ◽  
C. Clark ◽  
M. Duta ◽  
R. Cheesewright ◽  
M. Tombs
Keyword(s):  
Mass Flow ◽  
Flow Rate ◽  
Flow Meter ◽  
Coriolis Mass Flow Meter

scholarly journals Investigation of a non-invasive venous blood flow measurement device

2019 ◽  
Vol 5 (1) ◽  
pp. 179-182
Author(s):  
Kent Stewart ◽  
Simon Dangelmaier ◽  
Peter Pott ◽  
Jens Anders
Keyword(s):  
Blood Flow ◽  
Mass Flow ◽  
Flow Rate ◽  
Flow Measurement ◽  
Medical Condition ◽  
Venous Blood ◽  
Thermal Mass ◽  
Venous Blood Flow ◽  
Flow Meter ◽  
Non Invasive

AbstractVenous blood circulation can be restricted due to various conditions commonly indicating a related medical condition. However, current non-invasive methods for determining venous blood flow are limited to be either very inaccurate or expensive. Alternatively, a method to measure sap flow non-invasively in trees is through thermal mass measurement principles. This paper investigates applying the thermal mass flow measurement principle to determine venous blood flow. A simplified finite element model (FEM) and simulation are created to determine the operating behavior and expected response of a thermal mass flow meter with venous blood flow under the skin. An initial prototype of a thermal mass venous blood flow meter is designed using a Peltier-element and RTD thermistors. Initial tests were done on N = 8 subjects identifying the presence of blood flow and, testing the devices basic functionality and performance. The simplified FEM model of venous blood flow proved the thermal mass blood flow device is feasible, and determined the initial characteristics of the first prototype. The initial prototype proved to be functional detecting rises in temperature downstream of +1.4 K (0.8 - 1.8 inter- quartile range) when the blood flow was released (t = 90 s after release), compared to when blood was not flowing. The initial prototype proved to be able to detect the presence of blood flow in all subjects. However, further work is required to increase the differences in temperature values or gradient measured for a change in flow rate so the actual flow rate can be determined.

Sign in / Sign up

Export Citation Format

Share Document