Experimental comparison of specific heat capacity of three different metal oxides with MWCNT/ water-based hybrid nanofluids: proposing a new correlation

Abstract

The main objective of this study is to investigate three distinct non-commonly used metal oxide-based nanoparticles, i.e., CuO + MWCNT, MgO + MWCNT, and SnO 2 + MWCNT with a weight mixture ratio of 80:20 each (by weight ratio) and DI water as a base fluid along with the addition of the CTAB surfactant at 3:2. The study incorporates the effect of varying size, d p (20-50 nm), different temperature range (25-50 °C), and volume concentration range of 0.25-1.5%. After examining the stability of prepared HNF over the 30th day from the preparation day and some of the meticulous experimentation on isobaric heat capacity, a new correlation is developed to predict the specific heat of hybrid nanofluid. Considering various parameters like various volume concentration (φ = 0.25-1.50%) and temperature range (T = 25-50 ℃), specific heat of nanofluid, specific heat of base fluid, density of nanofluid, density of base fluid, and average diameter of used nanoparticles. The developed correlation was with 2.93% and 0.903% maximum and average absolute deviation, respectively. Experimental results show the maximum decrement in specific heat value is about 15.09% compared to base fluid DI water at 25 ℃ and 1.50% volume concentration with an average particle diameter of 20 nm for the MgO + MWCNT (80:20)/water HNF. However, it is found that the rate of decrement decreases with the increase of d p from 20 to 50 nm. From the current experimental results, it is concluded that the usage of HNF on relatively higher temperature significantly influences the overall thermophysical properties such as enhancement in thermal conductivity and decrement in viscosity of the working fluid, by paying the marginal loss in specific heat capacity. Therefore, it recommended that the usage of HNF on higher temperature is more beneficial for critical heat transfer application such as HVAC, effective thermal management of the system, natural and forced convection phenomenon.

Thermophysical Properties of Hybrid Nanofluids and the Proposed Models: An Updated Comprehensive Study

“…Aside from temperature and solid fraction, other factors, such as the size of particles and their types, influence the reduction in SH. For instance, Tiwari et al [65] measured the SH of different hybrid nanofluids, including CuO-MWCNT/water, MgO-MWCNT/water and SnO 2 -MWCNT/water, in different solid fractions, temperature and sizes of metal oxide particles (20 to 50 nm). They observed that in cases of the lower size of particles, a higher decrease in the SH occurred, which was attributed to the reduction in the density of the nanofluids due to the increase in particles size.…”

“…There are some models with improved comprehensiveness that are applicable for more than one nanofluid. For instance, Tiwari et al [65] proposed a correlation by considering the density, size and SH of nanoparticles besides temperature and VF for SH modeling of three different nanofluids, including CuO-MWCNT/water, MgO-MWCNT/water and SnO 2 -MWCNT/water. The maximum error of their model was 2.93%, while the average absolute relative error was 0.903%, demonstrating the high exactness of the model.…”

Hibrit nanoakışkanların özgül ısılarının yapay sinir ağları ile tahmin edilmesi

“…Bu çalışmada kullanılan veri seti 2020 yılının son çeyreğinde Tiwari vd. [26] tarafından yayımlanan makaleden elde edilmiştir. Deneysel çalışmalarında Tiwari vd.…”

“…Çalışmada Tiwari vd. [26] tarafından 2020 yılında yayımlanan makaledeki deneysel verilerden yararlanılmıştır. Geliştirilen kod ile hiper parametrelerin optimum değerleri Bayes optimizasyonu vasıtasıyla belirlenerek, elde edilen ağın azami performansa ulaştırılması hedeflenmiştir.…”

“…Son olarak, elde edilen YSA tabanlı tahminleyicinin performansı Tiwari vd. [26] tarafından önerilen korelasyonla karşılaştırılarak makina öğrenmesi modellerinin klasik korelasyonlara alternatif olarak kullanılıp kullanılamayacağı ve bu iki yaklaşımın birbirlerine göre avantajları ve dezavantajları üzerine derinlemesine bir değerlendirme yapılmıştır. Makalenin geri kalan kısmı şu şekilde organize edilmiştir: Bölüm 2'de çalışmada kullanılan veri setinden ve uygulanan yöntemin detaylarından bahsedilmiştir.…”