Base fluids generally have low thermal conductivity, but adding solid nanoparticles improves this property. In this research, spherical zinc oxide (ZnO) nanoparticles with diameters of 10-30, 35-45 and 80-100 nm were stabilized in ethylene glycol using a two-step method. CTAB surfactant and ultrasonic agitation were used to prevent particle aggregation. Nanofluids were prepared with volume fractions of 0.2 to 1% at temperatures of 20 to 60°C. Thermal conductivity was measured using the transient hot-wire method with a KD2-Pro device. Results showed that decreasing nanoparticle size, increasing temperature and increasing volume fraction significantly improved thermal conductivity, with the maximum increase (about 18%) observed at the highest temperature, smallest particle size and highest volume fraction. The effect of volume fraction was more remarkable at lower concentrations. Temperature increases facilitated heat transfer by weakening molecular bonds. Comparison of experimental data with analytical models showed that the difference between results increases with higher temperatures and volume fractions. Finally, a multivariate empirical model was developed and validated to predict the thermal conductivity of ZnO/EG nanofluid, which effectively describes the dependence of thermal conductivity on temperature, particle size and concentration.
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Safikhani,M , Ghafouri,A and moarrefzadeh,A . (2026). Development of a New Empirical Model for Predicting Thermal Conductivity of ZnO-Ethylene Glycol Nanofluid Based on Temperature, Particle Size, and Concentration. Science and Technology in Mechanical Engineering, 4(2), 175-189. doi: 10.22034/stme.2025.540032.1155
MLA
Safikhani,M , , Ghafouri,A , and moarrefzadeh,A . "Development of a New Empirical Model for Predicting Thermal Conductivity of ZnO-Ethylene Glycol Nanofluid Based on Temperature, Particle Size, and Concentration", Science and Technology in Mechanical Engineering, 4, 2, 2026, 175-189. doi: 10.22034/stme.2025.540032.1155
HARVARD
Safikhani M, Ghafouri A, moarrefzadeh A. (2026). 'Development of a New Empirical Model for Predicting Thermal Conductivity of ZnO-Ethylene Glycol Nanofluid Based on Temperature, Particle Size, and Concentration', Science and Technology in Mechanical Engineering, 4(2), pp. 175-189. doi: 10.22034/stme.2025.540032.1155
CHICAGO
M Safikhani, A Ghafouri and A moarrefzadeh, "Development of a New Empirical Model for Predicting Thermal Conductivity of ZnO-Ethylene Glycol Nanofluid Based on Temperature, Particle Size, and Concentration," Science and Technology in Mechanical Engineering, 4 2 (2026): 175-189, doi: 10.22034/stme.2025.540032.1155
VANCOUVER
Safikhani M, Ghafouri A, moarrefzadeh A. Development of a New Empirical Model for Predicting Thermal Conductivity of ZnO-Ethylene Glycol Nanofluid Based on Temperature, Particle Size, and Concentration. STME. 2026;4(2):175-189 (In Persian). doi: 10.22034/stme.2025.540032.1155
Science and Technology in Mechanical Engineering