The two-step method is used to prepare the nanofluids with kerosene as base fluid. Alumina or ferroferric oxide nano-particles were dispersed into kerosene. The mixture was mixed by an electric stirrer for 30 minutes, and then by ultrasonic oscillation for 45 minutes. The particle size distributions were analyzed by Malvern sizer. The alumina particles are without surface treatments, thus, oleic acid was used as addictive to make the alumina-kerosene nanofluid more stable. The ferroferric oxide particles are chemically treated by oleic acid, so they could be dispersed into kerosene with ease.
The experimental setup was built for supercritical heat transfer is shown as Fig. 1. The maximum pressure and temperature of the experimental section are 10 MPa and 600 °C, respectively. The critical pressure and temperature of kerosene are 2.390 MPa and 372.35 °C, respectively. So the system is suitable for the study of heat transfer characteristics of supercritical kerosene-base nanofluids.
The nanofluid goes from the reservoir, through a filter and reaches the pump. The pump provides the kinetic energy for the kerosene. As the piston pump provides unsteady liquid flow, a pulse damper is used to make the liquid flow more steady and constant. But before arriving at the flow meter, the liquid may goes to a safe loop, in case of dangerous situation when the liquid can goes back to the reservoir instead of going to the tested section. The flow rate is measured before the liquid is heated up. Then the liquid goes through the preheating and experimental sections, and become supercritical in the experimental section. The preheating and experimental sections are heated by direct current going through the tube wall. After the tested section, the liquid is condensed and recollected for further investigation and recycled uses.
In this project, the concentrations of the nanofluids were 0.1 wt%, 0.05wt% and 0.02wt%. Thus, I will analyze the effects of the particle concentrations, pressure, flow rate and heat flux. Now I have finished the experiments and am working on the data analysis. Wish that I could publish one or two papers on this topic!
Publications on this topic:
- X.Y. Wu, D. Huang, W. Li, G.Q. Xu, Z. Tao, P.X. Jiang, “Experimental Study on Heat Transfer of Fuel-Particle Mixtures in Vertical Tube at Supercritical Pressure”, ASME 2013 Heat Transfer Summer Conference, Minneapolis, 2013. FULLTEXT
- D. Huang, X. Y. Wu, Z. Wu, H. T. Zhu, W. Li, B. Sunden, “Experimental Studies on Heat Transfer of Nanofluids in a Vertical tube at Supercritical Pressures“,International Communications in Heat and Mass Transfer, 63 2015 54-61.FULLTEXT
- D. Huang, B. Ruan, X.Y. Wu, W. Zhang, G.Q. Xu, Z. Tao, P.X. Jiang, W. Li, “Experimental Study on Heat Transfer of Aviation Kerosene in a Vertical Upward Tube at Supercritical Pressures”, Chinese Journal of Chemical Engineering, 23 (2) 2015 425 – 434 FULLTEXT