Repeat Problem 8.52 for a circular tube of diameter \(D=2 \mathrm{~mm}\), an applied heat flux of \(q^{\prime \prime}=200,000 \mathrm{~W} / \mathrm{m}^{2}\), and a mass flow rate of \(\dot{m}=10 \mathrm{~g} / \mathrm{s}\).

Data From Problem 8.52:-

A circular tube of diameter \(D=0.2 \mathrm{~mm}\) and length \(L=100 \mathrm{~mm}\) imposes a constant heat flux of \(q^{\prime \prime}=20 \times\) \(10^{3} \mathrm{~W} / \mathrm{m}^{2}\) on a fluid with a mass flow rate of \(\dot{m}=0.1 \mathrm{~g} / \mathrm{s}\). For an inlet temperature of \(T_{m, i}=29^{\circ} \mathrm{C}\), determine the tube wall temperature at \(x=L\) for pure water. Evaluate fluid properties at \(\bar{T}=300 \mathrm{~K}\). For the same conditions, determine the tube wall temperature at \(x=L\) for the nanofluid of Example 2.2.

Data From Example 2.2:-

Transcribed Image Text:

The bulk thermal conductivity of a nanofluid containing uniformly dispersed, noncontact- ing spherical nanoparticles may be approximated by k+2k +20(k,- kb) kp+2k - pik - kb) where is the volume fraction of the nanoparticles, and kb, kp, and kf are the thermal con- ductivities of the base fluid, particle, and nanofluid, respectively. Likewise, the dynamic viscosity may be approximated as [20] Haf = Mbr (1 + 2.5pp) Determine the values of Kaf Pats Cp.nfs Hats and of for a mixture of water and Al2O3 nano- particles at a temperature of T = 300 K and a particle volume fraction of p = 0.05. The thermophysical properties of the particles are k = 36.0 W/m K, P = 3970 kg/m, and Cp.p=0.765 kJ/kg. K.