اصفهان: دانشگاه صنعتي اصفهان، دانشكده ‎مكانيك

1392

چهارده، 73ص: مصور، جدول، نمودار

ص.ع:به فارسي و انگليسي

احمد صداقت

محمد رضا سليم پور

25/09/1392

مهدي نيلي احمد آبادي، محمد رضا توكلي

‎مهندسي مكانيك

ID7671

به فارسي و انگلسيي: قابل رويت در نسخه ديجيتال

Experimental Study on Heat Transfer of TiO2 Nanofluid Flow in a Circular Tube with Twisted Tape Inserts Amir Houshmand A houshmand@me iut ac ir Department of Mechanical engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Ahmad Sedaghat Sedaghat@cc iut ac ir Abstract In order to meet the continuously increasing demand from industry electronics aerospace automotive and oil and gas refineries heat transfer equipments should be smaller lighter and with higher performanc Heat exchange fluids have an important role in increasing the thermal efficiency Nanoparticles increases the thermal conductivity of nanofluids heat transfer rates and imposing the dispersion of nanoparticles in base fluid and accelerates the process of energy conversion from the other point of view one of the methods to increasing is to use twisted tape in heat exchanger tubes This may increase the total heat transfer surface in a given volume and also cause an increase in mixing characteristic of flow leading to enhance heat transfer The purpose of this study is to experimentally investigate heat transfer enhancement using nanofluids with TiO2 nanoparticles inside the tubes with twisted tape inserts To achive this an experimental aparatus is designed and manufactured to study the effects of different parameters such as mass flow rate concentration of nanoparticles in suspension and with varying pitch distance of the twisted tapes The results of the enhanced heat transfer and pressure drops will be presented This study evaluates the performance of water TiO2 nanofluid for enhancing convective heat transfer in a heat exchanger tube with twisted tape inserts Factors considered include the twist ratio mass flow rate and the volumetric concentration of nano particles Experiments were conducted in a tube with constant wall temperature The nano particle volume concentration varies within the range of and the twisted tape inserts The Reynolds number variation is within the range of 3000 Re utilize twist ratio of 22000 The measured results revealed that the addition of nano particles as well as twisted tape inserts enhanced the convective heat transfer for all test cases Combining the positive effects of both nanofluid and the twisted tape the convective heat transfer was significantly increased up to 103 45 for the test case with volumetric concentration of 0 5 nanofluid and twist ratio of H D 5 However the addition of nanoparticles to the base fluid has marginally increased the pressure drop coefficient Appropriate correlations are introduced for the characteristics of the combined TiO2 water nanofluid and twisted tape inserts in circular tubes Keywords Experimental heat transfer TiO2 water nanofluid twisted tape Convection Constant wall temperature PDF created with pdfFactory trial version www pdffactory com

احمد صداقت

محمد رضا سليم پور

مهدي نيلي احمد آبادي، محمد رضا توكلي