Experimental study of heat transfer performance in a mini-corrugated pipe coupling nanofluids and pulsating wave

The combined application of nanofluids and pulsation was adopted to enhance heat transfer in a mini-channel corrugated tube. The corrugated tube provided a higher heat transfer capability than the smooth tube with the maximum Nu enhancement of 21.8% using distilled water (DW) as medium. When the heat transfer medium was replaced by 0.5%Al2O3/DW nanofluids, Nunf/Nubf increased by 16% at Re = 1100. Then, a pulsation wave generator with adjustable frequency and amplitude was designed. It was found there was an optimal St for each Re, and the lower the Re was, the higher the optimum St was. The optimum St for Re = 379, 730 and 1115 were 0.042, 0.03 and 0.024 respectively. When the pulsating frequency and pulsating amplitude (A) matched Re to obtain adequate fluid mixing, the maximum heat transfer coefficient was obtained. In the paper, the best heat transfer enhancement was 147% at St = 0.034, Re = 747 and A = 3.85.

Automated summary

The combination of nanofluids and pulsation was used to enhance heat transfer in a mini-channel corrugated tube, resulting in a maximum enhancement of 21.8% using distilled water as the medium. When 0.5% Al2O3/DW nanofluids were used as the heat transfer medium, Nunf/Nubf increased by 16% at Re = 1100. A pulsation wave generator was designed and the optimal St for each Re was determined, with lower Re values corresponding to higher optimum St values. The best heat transfer enhancement achieved in this study was 147% at St = 0.034, Re = 747, and A = 3.85.