Analysis of Flow and Heat Transfer Enhancement of Tube with Wire Coil Inserts Using MgO-Water Nanofluid

Abstract

Turbulent flow creates the laminar sub layer near the wall of fluid flowing tube. This laminar sub layer is destroyed by using various techniques. Tubes with wire coil inserts enhance the heat transfer rate by destroying laminar sub layer but it also create high pressure drop which increases pumping power. The present study on numerical investigation of thermo-hydraulic performance for tube with wire coil inserts by varying various parameter of wire coil inserts. Initially the wire coil diameter of 0.5 mm, 1mm and 1.5mm at pitch 28 mm is consider for analysis at the range of Reynolds number 4526 to 11313. Wire coil diameter of 1 mm gives highest thermo-hydraulic performance than other diameter. From the various pitch to diameter ratio 0.75, 0.86, 1 and 1.11; the highest thermo-hydraulic performance is found at 0.86 pitch to diameter ratio. The maximum enhancement in thermo-hydraulic performance of 66% is observed at Reynolds number 4526 for wire coil insert tube as compared to the smooth tube under similar working conditions. MgO water nanofluid of 0.005%, 0.01%, 0.05% and 0.1% volume concentration is used for the investigate heat transfer enhancement. 0.01% volume concentration gives maximum heat transfer rate with minimum pumping power. %. There was 39.69% increase in heat transfer coefficient at Reynolds number of 11317 for volume concentration of 0.01%. For wire coil inserted tube higher heat transfer coefficients are observed for nanofluid compared to distilled water at similar flow conditions. It was observed that there was 29.66% increase in heat transfer coefficient compared to distilled water at Reynolds number of 6790 using 0.01% MgO/Water nanofluid. It was observed that for coil inserted tube with 0.01% MgO/Water nanofluid as working fluid there was about 56% increase in heat transfer coefficient compared to smooth tube with distilled water as working fluid at 9053 Reynolds number