In a counter flow heat exchanger, hot fluid enters at 170°C & leaves at 150°C, while the cold fluid enters at 50°C & leaves at 70°C. The arithmetic mean temperature difference in this case is ______________ °C?

Related Mcqs:

1. In case of condensers & evaporators operating under given terminal conditions, LMTD (logarithmic mean temperature difference) for counter flow as compared to that for parallel flow is__________________?

   A. More
   B. Less
   C. Equal
   D. Much more

2. Parallel straight line pattern of temperature distribution for both hot and cold fluids is observed in case of heat exchanger of the type________________?

   A. Parallel flow with equal heat capacities
   B. Counter flow with equal heat capacities
   C. Counter flow with unequal heat capacities
   D. Parallel flow with unequal heat capacities

3. Temperature of hot gases flowing in a pipe is measured by a thermocouple inserted in the thermal well. The thermal well made of ______________ will facilitate the most accurate measurement of the temperature ?

   A. Copper
   B. Steel
   C. Aluminium
   D. Brass

4. Transition from laminar flow to turbulent flow in fluid flow through a pipe does not depend upon the___________________?

   A. Length of the pipe
   B. Diameter of the pipe
   C. Density of the fluid
   D. Velocity of the fluid

5. Out of the following, maximum temperature drop for a given heat flow & for the same thickness will be in the case of________________?

   A. Steel
   B. Glass wood
   C. Copper
   D. Fireclay bricks

6. Hot dipping process is used for coating a low melting point metal (e.g. Pb, Sn, Zn) on iron, steel & copper having relatively higher melting points. Which of the following is not a hot dipping process ?

   A. Galvanising
   B. Tinning
   C. Sherardizing
   D. None of these

7. Hot & cold working of material causes its _______________ deformation?

   A. Visco-elastic
   B. Isotropic
   C. Elastic
   D. Plastic

8. The most economical channel section for the fluid flow is the one for which the discharge is maximum for a given cross-sectional area. Vertical velocity distribution in an open channel for laminar flow can be assumed to be_______________?

   A. Parabolic
   B. Hyperbolic
   C. Straight line
   D. None of these

9. The difference in one unit of Rockwell hardness number corresponds to a difference in the depth of indentation of ______________ mm ?

   A. 0.001
   B. 0.01
   C. 0.002
   D. 0.02

10. Which of the following parameters is not responsible for the heat loss from a hot steam carrying bare pipe surface located in a room without fans ?

    A. Emissivity of pipe surface
    B. Diameter & length of the pipe
    C. Temperature of hot pipe surface & that of air in the room
    D. None of these