# Heat Transfer Enhancement of Nanofluids with Non-Spherical Nanoparticles: A Review
## 3 Convective Heat Transfer of NSN Nanofluids  
Convective heat transport occurs when the bulk motion of nanofluids transports energy. The migration of suspended nanoparticles is induced by fluid hydrodynamics and thermodynamics. Furthermore, the relative motion between particles and a fluid affects the hydrodynamics and thermodynamics of the fluid. The complex interaction between discrete and continuous phases shows differences under different particle morphologies and surface treatments, flow structures, and heat transfer conditions. In this section, the experimental and numerical studies of NSN nanofluids are reviewed. The pool boiling heat transfer studies are not discussed since they have been exhaustively covered in the  
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**Authors** & **Particle Shape** & **Models (\(\mathbf{k_{eff}}\)/\(\mathbf{k_{g}}\) as Default)** & **Remarks** \\ \hline [PERSON] et al. [57] & CNTs & \(\frac{3+(\frac{2\pi\beta_{1}^{2}-f_{g}}{2\pi^{2}+2\pi\beta}+\frac{\pi}{4}-1) \phi}{3-\frac{2\pi\beta_{1}^{2}-f_{g}^{2}}{\beta_{1}^{2}+f_{g}^{2}}\phi}\) & Incorporating the interface thermal resistance \\ [PERSON] [73] & CNTs & \(\frac{1-\phi+2\pi\beta_{1}^{2}\frac{\pi\beta_{1}^{2}+2\pi\beta_{2}}{2\pi^{2}+ 2\pi\beta_{2}}}{1-\phi+2\pi\beta_{1}^{2}\frac{\pi\beta_{1}^{2}+2\pi\beta_{2}^{ 2}}{2\pi^{2}+2\pi\beta_{2}^{2}}}\) & Based on Maxwell theory and considering the random CNT orientation distribution \\ [PERSON] and [PERSON] [58] & Ellipsoid & Complicated & Differential effective medium theory \\ [PERSON] et al. [74,75] & Cylinders/CNTs & \(\frac{\pi_{f}}{\Gamma_{f}}(\frac{2\pi_{f}}{2\pi_{f}+\phi})\left(0.35+0.56 \text{Re}_{f}^{0.52}\right)\text{Pr}_{f}^{0.3}\) & Interfacial layer theory Brownian motion is neglected \\ [PERSON] et al. [71] & CNTs & \(k_{eff}=\frac{\chi}{A}(\frac{N}{1-\frac{1}{\alpha_{\text{CNT}}}^{2}+\frac{1}{ \alpha_{\text{CNT}}^{2}+\frac{1}{\alpha_{\text{CNT}}^{2}}}})^{-1}\) & Assuming CNT contacts only two neighboring CNTs \\ [PERSON] et al. [72] & CNTs/CNFs & Based on model proposed by [71] & Excluded volume concept Monte Carlo simulation \\  & & \(k_{eff}=((k_{p}-k_{tr})\phi_{p}k_{tr}|\gamma_{1}^{2}-\gamma^{2}+1]\) & \\ [PERSON] et al. [59] & Cylinder & \(+(k_{p}+2k_{h})\times\gamma_{1}^{2}[\phi_{p}\gamma^{3}(k_{h}-k_{l})\) & Deduced in cylindrical coordinates \\  & & \(+k_{l}](\gamma_{1}^{3}(k_{p}+2k_{h})-\) & \\  & & \((k_{p}-k_{h})\Phi_{p}[\gamma_{1}^{3}+\gamma^{3}-1])^{-1}\) & \\ [PERSON] et al. [34] & Rods/bricks/ platelets/blades & \(1+(C_{br}^{sharp}+C_{br}^{sharp})\phi\) & Consider particle shape and interfacial contributions \\ [PERSON] et al. [61] & Arbitrary & \(\frac{k_{p}+(n-1)k+(n-1)(1+\beta^{*})\Phi(k_{h}-k)}{k_{p}+(n-1)k-(n-1)(n+\beta^ {*})\Phi(k_{h}-k)}+\frac{\Phi(T-T_{0})}{\mu\mu^{2}}\) & Consider interfacial layer, particle shape, and Brownian motion \\ [PERSON] et al. [78] & Cylinder & \(k=\frac{1}{3N\beta_{1}\pi^{2}}\int_{0}^{\infty}\langle 0/(0)(t)\rangle dt\) & MD simulation based on the Green-Kubo formula \\ [PERSON] et al. [60] & CNTs & \(\frac{k_{p}R(1+t/R-k_{p}/k_{p})\ln(1+t/R)}{\beta_{1}\ln[(1+t/R)k_{p}/k_{f}]} \beta_{1}=1+t/R\) & Interfacial layer theory \\  & & \(k_{eff}=\frac{1}{\pi}\int\limits_{0}^{\pi}\left(\frac{1}{\beta_{1}^{2}}\sin^{2 }\varphi+k_{p}^{2},\cos^{2}\varphi\right)^{1/2}d\varphi\) & Interfacial layer theory \\ [PERSON] et al. [64] & Cylinder & \(k_{eff}=k_{eff}/2\frac{2\pi\beta_{1}}{2\pi^{2}+2\pi\beta_{1}}+k_{eff}/2\frac{ R_{p}}{2\pi^{2}+2\pi\beta_{1}}\) & Interfacial layer theory \\  & & \(k_{eff2}=\frac{(k_{p}-k_{p})\Phi_{p}(\beta_{1}^{2}-\beta_{1}^{2}+1)+(k_{p}+k_{ p})\beta_{1}^{2}[\phi(k_{p}^{2}-k_{p})+k_{p}]}{\beta_{1 literature [8; 80; 81; 82]. In addition, CHT based on hybrid nanofluids is not included; the related studies have been reviewed by [PERSON] et al. [83]. Several recent studies have shown that hybrid nanofluids have significant potential as a coolant in solar cells [84; 85].