Experimental Study on Instability Behavior of Thermosyphon and Grooved Heat Pipe with TiO<sub>2</sub>-Nanofluid

Abstract

In the present study, TiO2-nanofluid with different volume ratio was used as working fluids of thermosyphon and grooved heat pipe to investigate working stability. The stability behavior of system was studied with various parameters such as volume concentration of nanoparticle, orientation, heat flux, and cooling media were investigated. Specially, the present experimental unstable working behaviors between TiO2-nanofluid and pure water were compared. In the present study, the TiO2-nanoparticles were dispersed into pure water with each of cross blended concentrations of 0.05%, 0.1%, 0.5%, and 1%. In the present study, the rate of growth of unstable disturbances is expressed in terms of temperature perturbation. The best stable operation was observed with thermosyphon of 0.5 % TiO2-nanofluid. The best operation state with nanofluidic TS was observed in the 90° inclination and α = 0.5. In the present study, the enhancement of heat pipe performance with TiO2-nanofluid is presented. The both heat pipes were fabricated from the straight stainless pipe with the inner diameter and length of 10, 500 mm, respectively.