Heat exchanger tubes are never made of Plain carbon steel Copper Stainless steel Lead TRUE ANSWER : ? YOUR ANSWER : ?
Overall thermal resistance for conductive heat transfer through a series of flat resistances is equal to the Average of all resistances Sum of all resistances Maximum resistance in the series Minimum resistance presents in the series TRUE ANSWER : ? YOUR ANSWER : ?
A concentric double pipe heat exchanger as compared to the shell and tube heat exchanger for the same heat load requires More space Less heating surface None of these Lower maintenance cost TRUE ANSWER : ? YOUR ANSWER : ?
Condensing film co-efficient for steam on horizontal tubes ranges from 5000 to 15000 Kcal/hr.m² .°C. Condensation of vapor is carried out inside the tube in a shell and tube heat exchanger, when the Temperature of the incoming vapor is very high Higher condensing film co-efficient is desired Lower pressure drop through the exchanger is desired Condensate is corrosive in nature TRUE ANSWER : ? YOUR ANSWER : ?
With increase in temperature, the thermal conductivity of non-metallic amorphous solids remains same decreases None of the listed here increases TRUE ANSWER : ? YOUR ANSWER : ?
Indirect contact heat exchangers are preferred over direct contact heat exchangers, because There is no mist formation Cost of equipment is lower Heat transfer co-efficient are high There is no risk of contamination TRUE ANSWER : ? YOUR ANSWER : ?
The heat transfer by radiation from a mild steel surface is to be reduced by reducing the emissivity of the surface. This can be best achieved by Painting the surface black Giving the surface a mirror finish Painting the surface white (with aluminium paint) Roughening the surface TRUE ANSWER : ? YOUR ANSWER : ?
The unit of heat transfer co-efficient in SI unit is J/M2°K W/m°K J/m°K W/m2°K TRUE ANSWER : ? YOUR ANSWER : ?
At what value of Prandtl number, conduction is negligible in the turbulent core of a fluid flowing through a heated pipe? 0.5 < 0.5 < 0.1 > 0.6 TRUE ANSWER : ? YOUR ANSWER : ?
The ratio of total radiating power to the absorptivity of the body depends upon the __________ as per Kirchoffs law. Wavelength of radiation Temperature of the body None of these Nature of the body TRUE ANSWER : ? YOUR ANSWER : ?