Measurement of quasi-local friction factor of gas flow in a micro-tube

Abstract

This paper presents experimental results on the friction factor of gaseous flow in a PEEK micro-tube with arithmetic mean roughness of 0.2 mm (relative surface roughness of 0.04%). The experiments were performed for nitrogen gas flow through the micro-tube with 514.4 mm in diameter and 50 mm in length. Three pressure tap holes were drilled on the PEEK micro-tube wall at intervals of 5 mm and the local pressures were measured. The quasi-local friction factor is obtained from the measured pressure differences. The experiments were conducted in the turbulent flow region. The quasi-local friction factor obtained from the present study is compared with those in the available literature and also numerical results. The quasi-local friction factor obtained is 12-20% higher than the value predicted from the Blasius formula.

Average Friction Factor for Laminar Gas Flow in Microtubes

“…The average Mach number between the inlet and the outlet can be defined as (4) where the average velocity, and the average temperature, can be obtained by integrating between the inlet (x 1 ) and outlet (x 2 ) as ,…”

“…A microchannel passage is the basic and important element in the design of micro flow devices and for this reason during the last decade a series of investigations have been conducted with the aim of clarifying the role of scale effects in microchannels [2]. From the early work by Wu and Little [3], numerous experimental and numerical investigations on microchannel gas flow have been undertaken as shown in the comprehensive review by Kawashima and Asako [4].…”

Data reduction of average friction factor of gas flow through adiabatic micro-channels

“…Kawashima and Asako [9] measured three local pressures near the outlet of a PEEK (polyether ether ketone) micro-tube with D = 514.4 m and L = 50 mm and obtained semi-local friction factors between two pressure ports that are located adjacently using Eqs. (2) and (4).…”