Experimental Investigation of Enhancement Heat Transfer by Natural Convection from Four Finned Cylinders in a Vertical Array Placed in a Conduit
Journal Title: International Journal of Mechanical and Production Engineering Research and Development (IJMPERD ) - Year 2019, Vol 9, Issue 5
Abstract
In this research, experiments have been implemented to enhance heat transfer by free convection from four finned cylinders that have helical fins, fixed horizontally inside conduit and using air as working fluid, the cylinders heated by electrical heaters at constant heat flux (188,341,573,832)W/m2 for Rayleigh number from (5ꓫ104 to 11.5ꓫ104 ) and Prandtl number (0.71)at the ambient temperature, approximately (24–26)oC and pressure at (1 atmosphere). The investigation include designed and manufactured test model, consist from two parts: moving and stationary, the stationary part is a frame made from iron that allows to move the part to inside it, according to ratio(H/D). The ratio (Y/D) changed four times (Y/D=2,4,6,8), the ratio (X/D) changed four times (X/D=1.5,3,5,7) and the ratio (H/D) changed four times (H/D=15,20,25,30). The results showed for all values of heat fluxes, the heat transfer coefficient and Nusselt number increases at separation distances (Y/D=4) & (X/D=3), which gives greater heat transfer rate, and any increasing or reducing lead to reduction in heat transfer rate. But regarding the ratio (H/D), the results showed there was no obvious influence or simple influence on heat transfer. Also, the results showed increased Nusselt number, with increasing Rayleigh number for all cylinders. The experiments have been implemented for single cylinder, placed in free air under constant heat flux, calculated (Nuo) and compared it with (Nui) for cylinders arranged in vertical array at the best case (Y/D=4) & (X/D=3) under the same heat flux (q ͌=341,573,832)W/m2 . The results show, there was obvious enhancement for the cylinders arranged in vertical array compared with singular cylinder in heat transfer, furthermore, this enhancement increases with increasing (Ra). From the results, empirical equation was found, to calculate the value of (Numean) that includes the two variables with (Ramean) as follows: Numean= 0.765Ra0.2 (Y/D) 0.08 (X/D) 0.01 (5ꓫ104≤ Ra ≤ 11.5ꓫ104).
Authors and Affiliations
Dr. Hassan K. Abdullah, Raad Y. Khudair
Keywords
Related Articles
- EP ID EP671647
- DOI 10.24247/ijmperdoct201920
- Views 99
- Downloads 0
The Investigations On Aluminium Substrates Coated With Micro-Sized WC-Co /Cr3C2-NiCr Multi-Layered Hard Coating
The aim of this paper is to analyze the enhanced properties of aluminium substrates by coating with multilayered hard coatings. In this study, coating containing alternative filmy layers of micro-sized chrome carbide– ni...
DFA & GRA based Multi Objective Optimization During Hot Machining of AISI D3 Tool Steel using TNMG Insert
In this paper, an experimental investigation is carried out to optimize performance characteristics (surface roughness and material removal rate) simultaneously in hot machining operation using Grey relational analysis (...
A Comparative Assessment of Tensile Strength and Corrosion Protection in Friction Stir Processed AA7075-T651 Matrix Composites using Fly Ashes Nanoparticles as Reinforcement Inhibitors in 3.5 % NaCl
This research presents the performance of eco-friendly waste materials, which are wood fly ash nanoparticle (WFA-NPs) and coal fly ash nanoparticles (CFA-NPs) as economical reinforcements corrosion inhibitors on friction...
Automatic Rebalancing of Radial Gates of the Spillway Dam in Cameroon
One of the problems facing hydroelectric plants is the imbalance of radial gates of the spillway dam. This imbalance causes the deterioration of lateral guiding seals, the deterioration of thermal relays, the deteriorati...
Use of Bond Graph Technique for Rotor Dynamic System Modelling and Comparative Analysis of Vibration Frequency using Fast Fourier Transform
This paper presents the bond graph model of a vibrating ,rotating shaft with disc mounted on it. Unbalance mass fitted to the disc cause the disc to vibrate. The bBond Graph technique has been used to model this vibratin...