Recent activity in Heat Transfer

A very long fin of a uniform square cross-section is replaced by another very long fin of a uniform circular cross-section of the same material. Assume uniform and identi...

Convective heat transfer coefficients for Fluid $1$ and Fluid $2$ in a heat exchanger, as shown in the figure below, are $50 \mathrm{~W} /\left(\mathrm{m}^{2} \mathrm{~K}...

Two rectangular surfaces both having $1 \mathrm{~m}^{2}$ area are placed perpendicular to each other with a common edge. One surface is hot, having a temperature of $1000...

A sphere of radius $5$ mm is initially in equilibrium at $400^{\circ} \mathrm{C}$ in a furnace. It is suddenly removed from the furnace and dipped in a well-stirred water...

A quiescent fluid at temperature $\mathrm{T}_{3}$ is confined between two vertical parallel plates. While plate $1$ is kept at temperature $\mathrm{T}_{1}$ and plate $2$ ...

During a welding operation, thermal power of $2500 \: W$ is incident normally on a metallic surface. As shown in the figure below (figure is NOT to scale), the heated are...

Consider a cylindrical furnace of $5 \: m$ diameter and $5 \:m$ length with bottom, top and curved surfaces maintained at uniform temperatures of $800 \mathrm{~K}, 1500 \...

Water enters a tube of diameter, $\mathrm{D}=60 \mathrm{~mm}$ with mass flow rate of $0.01 \mathrm{~kg} \mathrm{~s}^{-1}$ as shown in the figure below. The inlet mean tem...

In a furnace, the inner and outer sides of the brick wall $(k_1=2.5 \: \text{W/m.k})$ are maintained at $1100 ^\circ C$ and $700 ^\circ C$, respectively as shown in figur...

​Consider a hydrodynamically fully developed laminar flow through a circular pipe with the flow along the axis (i.e., $z$ direction). In the following statements, $T$ is ...

​​​​​Consider incompressible laminar flow over a flat plate with freestream velocity of $u_{\infty}$. The Nusselt number corresponding to this flow velocity is $N u_{1}$....

​​​​A plane, solid slab of thickness $L$, shown in the figure, has thermal conductivity $k$ that varies with the spatial coordinate $x$ as $k=A+B x$, where $A$ and $B$ ar...

A heat pump $\text{(H.P.)}$ is driven by the work output of a heat engine $\text{(H.E.)}$ as shown in the figure. The heat engine extracts $150 \mathrm{~kJ}$ of heat from...

Consider a hemispherical furnace of diameter $\text{D}=6 \mathrm{~m}$ with a flat base. The dome of the furnace has an emissivity of $0.7$ and the flat base is a blackbod...

A condenser is used as a heat exchanger in a large steam power plant in which steam is condensed to liquid water. The condenser is a shell and tube heat exchanger which c...

Consider a slab of $20 \mathrm{~mm}$ thickness. There is a uniform heat generation of $\dot{q}=100 \mathrm{MW} / \mathrm{m}^{3}$ inside the slab. The left and right faces...

Consider incompressible laminar flow of a constant property Newtonian fluid in an isothermal circular tube. The flow is steady with fully-developed temperature and veloci...

Consider a laterally insulated rod of length $\mathrm{L}$ and constant thermal conductivity. Assuming one-dimensional heat conduction in the rod, which of the following s...

Consider a counter-flow heat exchanger with the inlet temperatures of two fluids $(1$ and $2)$ being $T_1$, in $=300 \mathrm{~K}$ and $T_2$, in $=350 \mathrm{~K}$. The he...

A cylindrical rod of length $h$ and diameter $d$ is placed inside a cubic enclosure of side length $L. S$ denotes the inner surface of the cube. The view-factor $F_{S-S}$...

A very large metal plate of thickness $d$ and thermal conductivity $k$ is cooled by a stream of air at temperature $T_{\infty}=300 \mathrm{~K}$ with a heat transfer coeff...

Which of the following non-dimensional terms is an estimate of Nusselt number?Ratio of internal thermal resistance of a solid to the boundary layer thermal resistanceRati...

Wien's law is stated as follows: $\lambda _{m}T = C$, where $C$ is $2898$ $\mu m \cdot K$ and $\lambda_{m}$ is the wavelength at which the emissive power of a black body ...

Consider steady state, one-dimensional heat conduction in an infinite slab of thickness $2L (L = 1\:m)$ as shown in the figure. The conductivity $(k)$ of the material var...

Saturated vapor at $200\: ^{\circ}C$ condenses to saturated liquid at the rate of $150$ $\text{kg/s}$ on the shell side of a heat exchanger (enthalpy of condensation $h_{...

Consider a hydrodynamically and thermally fully-developed, steady fluid flow of $1$ $\text{kg/s}$ in a uniformly heated pipe with diameter of $0.1\: m$ and length of $40 ...

Solution of $\triangledown ^{2} T = 0$ in a square domain ($0 < x< 1$ and $0 < y< 1$) with boundary conditions: $T \left ( x,0 \right ) = x; T \left ( 0,y \right ) = y; T...

Consider a rod of uniform thermal conductivity whose one end $(x = 0)$ is insulated and the other end $(x =L)$ is exposed to flow of air at temperature $T_{\infty}$ with ...