Computation of transient flow rates in passive pumping micro-fluidic systems

I-Jane Chen; Eugene C. Eckstein; Ernő Lindner

doi:10.1039/b808660e

Unsteady Radial Flow of Gas Through Porous Media

Journal of Applied Mechanics ◽

10.1115/1.4010651 ◽

1953 ◽

Vol 20 (2) ◽

pp. 210-214

Author(s):

R. Jenkins ◽

J. S. Aronofsky

Keyword(s):

Porous Medium ◽

Porous Media ◽

Radial Flow ◽

Transient Flow ◽

Gas Reservoirs ◽

Punch Card ◽

Flow Rates ◽

Pressure Distributions ◽

History Of ◽

Natural Gas Reservoirs

Abstract This paper presents a numerical method for describing the transient flow of gases radially inward or outward through a porous medium in which the initial and terminal pressures and/or rates are specified. Specific examples are worked out which have application in the study of natural-gas reservoirs. The computations were carried out by means of punch-card machines. The pressure distribution as a function of time has been calculated for various ratios of reservoir diameter to well diameter and for various dimensionless flow rates for a well penetrating the center of a homogeneous disk-shaped reservoir. A simple means of predicting the well pressure at any time in the history of such an idealized field has been developed. Flow rates and pressure distributions within the radial reservoir also have been calculated for the case in which the well pressure is suddenly lowered from its initial static value, and then held constant.

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Transient Flow of the Oil-Refrigerant Mixture Through the Radial Clearance in Rolling Piston Compressors

10.1115/imece1999-0818 ◽

1999 ◽

Author(s):

José L. Gasche ◽

Rogério T. S. Ferreira ◽

Álvaro T. Prata

Keyword(s):

Mass Flow ◽

Transient Flow ◽

Tangential Velocity ◽

Radial Clearance ◽

Compression Process ◽

Mixture Flow ◽

Important Conclusion ◽

Flow Rates ◽

Mass Flow Rates ◽

Rolling Piston

Abstract Unsteady flow of oil and refrigerant gas through radial clearance in rolling piston compressors has been modeled as a heterogeneous mixture, where the properties are determined from the species conservation transport equation coupled with momentum and energy equations. Time variations of pressure, tangential velocity of the rolling piston and radial clearance due to pump setting have been included in the mixture flow model. Those variables have been obtained by modeling the compression process, rolling piston dynamics and by using geometric characteristics of the pump, respectively. An important conclusion concerning this work is the large variation of refrigerant concentration in the oil-filled radial clearance during the compression cycle. That is particularly true for large values of mass flow rates, and for those cases the flow mixture cannot be considered as having uniform concentration. In presence of low mass flow rates homogeneous flow prevail and the mixture tend to have a uniform concentration. In general, it was observed that for calculating the refrigerant mass flow rate using the difference in refrigerant concentration between compression and suction chambers, a time average value for the gas concentration should be used at the clearance inlet.

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Experimental study to establish an evaluating method for the responsiveness of liquid flowmeters to transient flow rates

Flow Measurement and Instrumentation ◽

10.1016/j.flowmeasinst.2021.102067 ◽

2021 ◽

pp. 102067

Author(s):

Noriyuki Furuichi ◽

Cheong Kar-Hooi ◽

Taiki Yoshida

Keyword(s):

Experimental Study ◽

Transient Flow ◽

Flow Rates ◽

Evaluating Method

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Instantaneous Liquid Flow Rate Measurement Utilizing the Dynamic Characteristics of Laminar Flow in Circular Pipes

Volume 2: Symposia, Parts A, B, and C ◽

10.1115/fedsm2003-45613 ◽

2003 ◽

Cited By ~ 1

Author(s):

Bernhard Manhartsgruber

Keyword(s):

Laminar Flow ◽

Flow Rate ◽

Dynamic Characteristics ◽

Transient Flow ◽

Indirect Measurement ◽

Inverse Laplace Transform ◽

Flow Rates ◽

Flow Ripple ◽

Pipe Section ◽

Circular Pipes

The instantaneous measurement of transient flow rates is an important problem in many fluid power applications such as the investigation of the flow ripple generated by hydraulic pumps or the measurement of flow rate changes at the ports of fast switching valves. This paper deals with the utilization of the dynamic characteristics of laminar flow in circular pipes for the indirect measurement of flow rates. A discrete time state space realization of the transmission line dynamics is computed via inverse Laplace transform and an identification and model reduction method based on the singular value decomposition. This dynamic system is used for the computation of the flow rate at one end of a pipe section. Special attention is paid to the identification of the speed of sound and the dimensionless dissipation number of the pipe section, since exact knowledge of these parameters is crucial for the reliabilty of the measurement results.

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Modeling and Experimental Characterization of Pressure Drop in Gravity-Driven Microfluidic Systems

Journal of Fluids Engineering ◽

10.1115/1.4028501 ◽

2014 ◽

Vol 137 (2) ◽

Cited By ~ 15

Author(s):

Antti-Juhana Mäki ◽

Samu Hemmilä ◽

Juha Hirvonen ◽

Nathaniel Narra Girish ◽

Joose Kreutzer ◽

...

Keyword(s):

Microfluidic Systems ◽

Flow Rates ◽

Driven Systems ◽

Pumping System ◽

Proposed Model ◽

Gravity Driven ◽

Passive Pumping ◽

Gravity Driven Flow ◽

Real Flow

Passive pumping using gravity-driven flow is a fascinating approach for microfluidic systems. When designing a passive pumping system, generated flow rates should be known precisely. While reported models used to estimate the flow rates do not usually consider capillary forces, this paper shows that their exclusion is unrealistic in typical gravity-driven systems. Therefore, we propose a new analytical model to estimate the generated flow rates. An extensive set of measurements is used to verify that the proposed model provides a remarkably more precise approximation of the real flow rates compared to the previous models. It is suggested that the developed model should be used when designing a gravity-driven pumping system.

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A Novel Self-Activated Mechanism for Stable Liquid Transportation Capable of Continuous-Flow and Real-time Microfluidic PCRs

Micromachines ◽

10.3390/mi10060350 ◽

2019 ◽

Vol 10 (6) ◽

pp. 350 ◽

Cited By ~ 1

Author(s):

Di Wu ◽

Bing Shi ◽

Bin Li ◽

Wenming Wu

Keyword(s):

Mathematical Modeling ◽

Real Time ◽

Continuous Flow ◽

Transport Mechanism ◽

The Self ◽

Amplification Efficiency ◽

Passive Transport ◽

Flow Rates ◽

Quartz Capillary ◽

Passive Pumping

The self-activated micropump capable of velocity-stable transport for both single-phased plug and double-phased droplet through long flow distance inside 3D microchannel is one dream of microfluidic scientists. While several types of passive micropumps have been developed based on different actuation mechanisms, until today, it is still one bottleneck to realize such a satisfied self-activated micropump for the stable delivery of both single and double-phased liquid inside long microchannel (e.g., several meters), due to the lack of innovative mechanism in previous methods. To solve this problem, in this article, we propose a new self-activated pumping mechanism. Herein, an end-opened gas-impermeable quartz capillary is utilized for passive transport. Mechanism of this micropump is systemically studied by both the mathematical modeling and the experimental verifications. Based on the flow assays, it totally confirmed a different pumping principle in this paper, as compared with our previous works. The R 2 value of the overall flow rates inside the 3D microchannel is confirmed as high as 0.999, which is much more homogeneous than other passive pumping formats. Finally, this novel micropump is applied to continuous-flow real-time PCRs (both plug-type and microdroplet-type), with the amplification efficiency reaching 91.5% of the commercial PCR cycler instrument.

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Automation of Process Control in Chemical Plant

ACMIT Proceedings ◽

10.33555/acmit.v2i1.3 ◽

2015 ◽

Vol 2 (1) ◽

pp. 6-12

Author(s):

Agus Sugiarta ◽

Houtman P. Siregar ◽

Dedy Loebis

Keyword(s):

Process Control ◽

Pid Control ◽

Control Algorithm ◽

Chemical Engineering ◽

Chemical Plant ◽

Raw Material ◽

Flow Rates ◽

Material Supply ◽

Wide Range ◽

Inherent Problem

Automation of process control in chemical plant is an inspiring application field of mechatronicengineering. In order to understand the complexity of the automation and its application requireknowledges of chemical engineering, mechatronic and other numerous interconnected studies.The background of this paper is an inherent problem of overheating due to lack of level controlsystem. The objective of this research is to control the dynamic process of desired level more tightlywhich is able to stabilize raw material supply into the chemical plant system.The chemical plant is operated within a wide range of feed compositions and flow rates whichmake the process control become difficult. This research uses modelling for efficiency reason andanalyzes the model by PID control algorithm along with its simulations by using Matlab.

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