Experimental and numerical research on the flow and heat transfer characteristics of TiO2-water nanofluids in a corrugated tube

Flow resistance and enhanced heat transfer characteristics of TiO2-water nanofluids in a stainless-steel corrugated tube and a circular tube are investigated by experimental and numerical methods respectively. The flow and heat transfer characteristics of TiO2-water nanofluids and deionized water in test tubes are compared in this paper. In addition, effects of Reynolds number (Re) and nanoparticle mass fraction (ω) on flow and heat transfer performances are discussed respectively, and Nusselt number (Nu) and resistance coefficient (f) are studied respectively. Finally, comprehensive performance of flow resistance and heat transfer enhancement is evaluated. It can be obtained that adding nanoparticle into deionized water doesn't cause a large additional resistance loss in some degree, while the combination of corrugated tube and TiO2-water nanofluids shows an excellent heat transfer enhancement, which can enhance the heat transfer by 53.95% at maximum extent. In addition, the corrugated tube has a strong sustainability in enhancing heat transfer. The enhanced heat transfer rising part (6000 ≤ Re ≤ 10,000) has a large rising slope (about 7.90E−5), and the descending slope (about 7.16E−6) of enhanced heat transfer part (10,000 ≤ Re ≤ 12,000) is small.