A heat exchanger has been designed with heat transfer surface area of ‘A’ and overall heat transfer coefficient ‘U’, handling two different fluids of heat capacities $ C_{\text{min}} $ and $ C_{\text{max}} $. The parameter NTU used in the analysis of heat exchanger is specified as:
Show Hint
- \( \frac{A U}{C_{\text{max}}} \)
- \( \frac{C_{\text{max}}}{A U} \)
- \( \frac{A U}{C_{\text{min}}} \)
- \( \frac{C_{\text{min}}}{A U} \)
The Correct Option is C
Solution and Explanation
The number of transfer units (NTU) in heat exchanger analysis is defined as: \[ \text{NTU} = \frac{A U}{C_{\text{min}}} \] Where: \( A \) is the heat transfer area,
\( U \) is the overall heat transfer coefficient,
\( C_{\text{min}} \) is the minimum heat capacity rate.
Step 2: Conclusion
Thus, the correct expression for NTU is \( \boxed{\frac{A U}{C_{\text{min}}}} \).
Top Questions on Heat Transfer
One mole of an ideal gas at 300 K is compressed isothermally from a volume of \(V_1\) to \(V_2\). Calculate:
The work done on the gas
The change in internal energy
The heat exchanged with the surroundings
Use \(R = 8.314\, \text{J/molK}\), \( \ln(2.5) = 0.916\)- AP EAPCET - 2025
- Physics
- Heat Transfer
Three conductors of same length having thermal conductivity \(k_1\), \(k_2\), and \(k_3\) are connected as shown in figure. Area of cross sections of 1st and 2nd conductor are same and for 3rd conductor it is double of the 1st conductor. The temperatures are given in the figure. In steady state condition, the value of θ is ________ °C. (Given: \(k_1\) = 60 Js⁻¹m⁻¹K⁻¹,\(k_2\) = 120 Js⁻¹m⁻¹K⁻¹, \(k_3\) = 135 Js⁻¹m⁻¹K⁻¹)
- JEE Main - 2025
- Physics
- Heat Transfer
- Two spherical bodies of same materials having radii 0.2 m and 0.8 m are placed in same atmosphere. The temperature of the smaller body is 800 K and temperature of bigger body is 400 K. If the energy radiate from the smaller body is E, the energy radiated from the bigger body is (assume, effect of the surrounding to be negligible):
- JEE Main - 2025
- Physics
- Heat Transfer
- Two cylindrical rods A and B made of different materials, are joined in a straight line. The ratio of lengths, radii and thermal conductivities of these rods are : $ \frac{L_A}{L_B} = \frac{1}{2} $, $ \frac{r_A}{r_B} = 2 $, and $ \frac{K_A}{K_B} = \frac{1}{2} $. The free ends of rods A and B are maintained at $ 400 \, K $, $ 200 \, K $, respectively. The temperature of rods interface is ____ K, when equilibrium is established.
- JEE Main - 2025
- Physics
- Heat Transfer
- A wire of length 10 cm and diameter 0.5 mm is used in a bulb. The temperature of the wire is 1727°C and power radiated by the wire is 94.2 W. Its emissivity is $ \frac{x}{8} $, where $ x = \ldots $
- JEE Main - 2025
- Physics
- Heat Transfer
Questions Asked in TS PGECET exam
A shaft has diameter $20^{+0.05}_{-0.15}$ mm and a hole diameter $20^{+0.20}_{-0.10}$ mm. When these are assembled, then what is the nature of fit yield?
- TS PGECET - 2024
- Metrology and Inspection
- Hungarian method is generally used to solve the following type of problem:
- TS PGECET - 2024
- Operations Research
- In critical path method, critical path moves along with the activities having total float of:
- TS PGECET - 2024
- Operations Research
- The product 'A' has the demand of 1000 with ordering cost Rs 100/- per order with a holding cost of Rs 40/- per year. Another product 'B' has the demand of 3600 with the ordering cost of Rs 100/- per year with a holding cost of Rs 100/- per year. What is the ratio of EOQs 'B' to 'A'?
- TS PGECET - 2024
- Inventory Control
- The optimality of a transportation problem is determined by the application of:
- TS PGECET - 2024
- Operations Research