A novel method for calculating the dynamic capillary force and correcting the pressure error in micro-tube experiment

Abstract

Micro-tube experiment has been implemented to understand the mechanisms of governing microcosmic fluid percolation and is extensively used in both fields of micro electromechanical engineering and petroleum engineering. The measured pressure difference across the microtube is not equal to the actual pressure difference across the microtube. Taking into account the additional pressure losses between the outlet of the micro tube and the outlet of the entire setup, we propose a new method for predicting the dynamic capillary pressure using the Level-set method. We first demonstrate it is a reliable method for describing microscopic flow by comparing the micro-model flow-test results against the predicted results using the Level-set method. In the proposed approach, Level-set method is applied to predict the pressure distribution along the microtube when the fluids flow along the microtube at a given flow rate; the microtube used in the calculation has the same size as the one used in the experiment. From the simulation results, the pressure difference across a curved interface (i.e., dynamic capillary pressure) can be directly obtained. We also show that dynamic capillary force should be properly evaluated in the micro-tube experiment in order to obtain the actual pressure difference across the microtube.

Flow Boiling of Liquid n-Heptane in Microtube with Various Fuel Flow Rate: Experimental and Numerical Study

“…This decrease in density further increases the velocity, and as a result, the pressure of the vapor phase increases. Wang et al [ 53 ] estimated the capillary pressure in the stable flow using the following formula: where P l , P c , and P v are liquid pressure, capillary pressure, and vapor pressure, respectively. The interfacial tension present at the contact causes capillary pressure.…”

“…This decrease in density further increases the velocity, and as a result, the pressure of the vapor phase increases. Wang et al [53] estimated the capillary pressure in the stable flow using the following formula:…”

A Novel Relative Permeability Model for Gas and Water Flow in Hydrate-Bearing Sediments With Laboratory and Field-Scale Application

“…Similarly, for the purpose of developing an analytical relative permeability model for gas hydrate per the Purcell's approach, a capillary pressure equation that can be integrated is required. Many studies have proposed different methods to predict capillary pressure, including analytical [25][26][27][28] and numerical methods 29 , but the choice of a capillary function used in this study is based on two requirements, which are: (i) it can be integrated analytically, and (ii) it is applicable to a porous medium. Based on these two conditions, a general capillary pressure model reported by Li 25 is used as an expression to derive the proposed relative permeability model for gas hydrate-bearing sediments.…”

Tricore photonic crystal fibre based refractive index sensor for glucose detection

“…The extension of this RI sensor was also said to be possible using the microstructure optical fibre [42] known as PCF's and its experimental characteristics for different sensing liquid taken in a hollow channel while propagating the nanosecond pulses in solid silica core were investigated. The other practical method of infiltrating any liquid analyte into the capillary tube of PCF is followed by selective filling method [43], selective infiltration assistance of femtosecond laser micromachining [44] and capillary force method [45] if it is smaller in dimension. Sometimes, the arc discharge pre-treatment [46] is trailed at the inlet side of the fibre so that the PCF sensor can be reused for other sensing applications.…”