MCQOPTIONS
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MCQOPTIONS
This section includes 8 Mcqs, each offering curated multiple-choice questions to sharpen your Heat Transfer knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
CONSIDER_THE_ABOVE_PROBLEM,_FIND_THE_STEAM_CONDENSATION_RATE?$ |
| A. | 52.22 kg/hr |
| B. | 42.22 kg/hr |
| C. | 32.22 kg/hr |
| D. | 22.22 kg/hr |
| Answer» E. | |
| 2. |
NTU_is_a_number_of_transfer_units,_dimensionless_parameter_defined_as$ |
| A. | U A/C <sub>MIN</sub> |
| B. | 2 U A/C <sub>MIN</sub> |
| C. | 3 U A/C <sub>MIN</sub> |
| D. | 4 U A/C <sub>MIN</sub> |
| Answer» B. 2 U A/C <sub>MIN</sub> | |
| 3. |
In a surface condenser, the water flowing through a series of tubes at the rate of 200 kg/hr is heated from 15 degree Celsius to 75 degree Celsius. The steam condenses on the outside surface of tubes at atmospheric pressure and the overall heat transfer coefficient is estimated at 860 k J/m2 hr degree. Find the number of transfer units of the heat exchanger. At the condensing pressure, stream has saturation temperature 0f 100 degree Celsius and the latent heat of vaporization is 2160 k J/kg. Further, the steam is initially just saturated and the condensate leaves the exchanger without sub-cooling i.e. only latent heat of condensing steam is transferred to water. Take specific heat of water as 4 k J/kg ? |
| A. | 3.224 |
| B. | 2.224 |
| C. | 1.224 |
| D. | 0.224 |
| Answer» D. 0.224 | |
| 4. |
The engine oil at 150 degree Celsius is cooled to 80 degree Celsius in a parallel flow heat exchanger by water entering at 25 degree Celsius and leaving at 60 degree Celsius. Estimate the number of transfer units |
| A. | 1.221 |
| B. | 2.221 |
| C. | 3.221 |
| D. | 4.221 |
| Answer» B. 2.221 | |
| 5. |
E – NTU method is particularly useful in thermal design of heat exchangers when$ |
| A. | Inlet temperature of the fluid streams are not known as a priori |
| B. | The outlet temperatures of the hot fluid streams is known but that of cold fluid stream is not known as a priori |
| C. | The outlet temperatures of the fluid streams is known as a priori |
| D. | The outlet temperatures of the fluid streams are not known as a priori |
| Answer» E. | |
| 6. |
After expansion from a gas turbine, the hot exhaust gases are used to heat the compressed air from a compressor with the help of a cross flow heat exchanger of 0.8 effectiveness. What is the number of transfer units of the heat exchanger? |
| A. | 2 |
| B. | 4 |
| C. | 8 |
| D. | 16 |
| Answer» C. 8 | |
| 7. |
In a balanced counter flow heat exchanger with m h c h = m c c c, the NTU is equal to unity. What is the effectiveness of heat exchanger? |
| A. | 0.5 |
| B. | 1.5 |
| C. | 0.33 |
| D. | 0.2 |
| Answer» B. 1.5 | |
| 8. |
A cross flow type air heater has an area of 50 cm2. The overall heat transfer coefficient is 100 W/m2 K and heat capacity of both hot and cold stream is 1000 W/m K. The value of NTU is |
| A. | 1000 |
| B. | 500 |
| C. | 5 |
| D. | 0.2 |
| Answer» C. 5 | |