The effect of oscillations on the heat transfer in a vertical tube has been studied experimentally. A vertical tube was mounted on a plate and the whole plate was subjected to oscillations in the vertical plane using a mechanical oscillator to provide low frequency oscillations. A section of the tube in the middle is subjected to a constant heat flux. The effect of the oscillations on the heat transfer coefficient has been examined. It was found that the heat transfer coefficient increased with oscillations in the laminar regime. In turbulent flow regime (Re > 2,100) it is found that the effect of oscillations did not show any change. A correlation has been developed for enhancement of the local Nusselt number in terms of the effective acceleration and Reynolds number. Using this, an expression has been proposed to calculate the mean Nusselt number as a function of the tube length. © 2007 Springer-Verlag.

Sreenivas Jayanti

Department Of Chemical Engineering

Arcot R. Balakrishnan

Nusselt number

Plates (structural components)

Reynolds number

Tubes (components)

Variable frequency oscillators

AXIAL LOW FREQUENCY OSCILLATIONS

SINGLE PHASE FLOW

VERTICAL TUBES

Heat convection

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Heat and Mass Transfer/Waerme- und Stoffuebertragung

Heat transfer and other equipment mounted on off-shore platforms may be subjected to low frequency oscillations. The effect of these oscillations, typically in the frequency range of 0.1-1 Hz, on the flow rate and pressure drop in a vertical tube has been studied experimentally in the present work. A 1.75 m-long vertical tube of inner diameter 0.016 m was mounted on a plate and the whole plate was subjected to oscillations in the vertical plane using a mechanical simulator capable of providing low frequency oscillations in the range of 8-30 cycles/min at an amplitude of 0.125 m. The effect of the oscillations on the flow rate and the pressure drop has been measured systematically in the Reynolds number range 500-6500. The induced flow rate fluctuations were found to be dependent on the Reynolds number with stronger fluctuations at lower Reynolds numbers. The effective friction factor, based on the mean pressure drop and the mean flow rate, was also found to be higher than expected. Correlations have been developed to quantify this Reynolds number dependence. © 2007 Elsevier B.V. All rights reserved.

Nuclear Engineering and Design

Flow and pressure drop fluctuations in a vertical tube subject to low frequency oscillations

Nuclear Power Plant Operating Experience from the IAEA/NEA International Reporting System for Operating Experience 2015-2017

Heat and Mass Transfer

An experimental investigation of heat transfer to pulsating pipe air flow with different amplitudes

International Journal of Heat and Mass Transfer

An analytical study of pulsating laminar heat convection in a circular tube with constant heat flux

Convective heat transfer characteristics of laminar pulsating pipe air flow

Convective heat transfer in single-phase flow in a vertical tube subjected to axial low frequency oscillations

Journal	Heat and Mass Transfer/Waerme- und Stoffuebertragung
ISSN	09477411
Open Access	No