1
GATE ME 2017 Set 2
+2
-0.6
In a counter-flow heat exchanger, water is heated at the rate of $$1.5kg/s$$ from $$\,40{}^ \circ C\,$$ to $$\,80{}^ \circ C\,$$ by an oil entering at $$\,120{}^ \circ C\,$$ and leaving at $$\,60{}^ \circ C\,$$. The specific heats of water and oil are $$4.2kJ/kgK$$ and $$2kJ/kgK,$$ respectively. The overall heat transfer coefficient is $$400\,W/{m^2}K.$$ The required heat transfer surface are (in $${m^2}$$) is
A
$$0.104$$
B
$$0.022$$
C
$$10.4$$
D
$$21.84$$
2
GATE ME 2016 Set 2
Numerical
+2
-0
Consider a parallel-flow heat exchanger with area $${A_p}$$ and a counter-flow heat exchanger with area $${A_c}.$$ In both the heat exchangers, the hot stream flowing at $$1$$ $$kg/s$$ cools from $$80{}^ \circ C$$ to $$50{}^ \circ C$$. For the cold stream in both the heat exchangers, the flow rate and the inlet temperature are $$2$$ $$kg/s$$ and $$10{}^ \circ C$$, respectively. The hot and cold streams in both the heat exchangers are of the same fluid. Also, both the heat exchangers have the same overall heat transfer coefficient. The ratio $${A_c}/{A_p}$$ is ______________
3
GATE ME 2015 Set 2
+2
-0.6
A balanced counter-flow heat exchanger has a surface area of $$20\,\,{m^2}$$ and overall heat transfer coefficient of $$20$$ $$W/{m^2}$$-$$K$$. Air $$\left( {{C_p} = 1000J/kg - K} \right)$$ entering at $$0.4$$ $$kg/s$$ and $$280$$ $$K$$ is to preheated by the air leaving the system at $$0.4$$ $$kg/s$$ and $$300$$ $$K.$$ The outlet temperature (in $$K$$) of the preheated air is
A
$$290$$
B
$$300$$
C
$$320$$
D
$$350$$
4
GATE ME 2014 Set 2
Numerical
+2
-0
In a concentric counter flow heat exchanger, water flows through the inner tube at $${25^ \circ }C$$ and leaves at $${42^ \circ }C$$. The engine oil enters at $${100^ \circ }C$$ and flows in the annular flow passage. The exit temperature of the engine oil is $${50^ \circ }C.$$ Mass flow rate of water and the engine oil are $$1.5kg/s$$ and $$1$$ $$kg/s,$$ respectively. The specific heat of water and oil are $$4178$$ $$J/kg.K$$ and $$2130$$ $$J/kg.K,$$ respectively. The effectiveness of this heat exchanger is _________.
GATE ME Subjects
Engineering Mechanics
Machine Design
Strength of Materials
Heat Transfer
Production Engineering
Industrial Engineering
Turbo Machinery
Theory of Machines
Engineering Mathematics
Fluid Mechanics
Thermodynamics
General Aptitude
EXAM MAP
Joint Entrance Examination