ISRO Scientist or Engineer Mechanical 2013
For the following questions answer them individually
A venturimeter. of 20mm throat diameter is used to measure the velocity of water.in a horizontal pipe of 40mm diameter. If the pressure difference between the pipe and throat sections is found to be 30 kPa, then, neglecting frictional losses, the flow velocity is
A room contains 60 kg of air at 100 kPa and $$15^\circ$$C. The room has a 250-W refrigerator (the refrigerator consumes 250 W of electricity when running), a 120-W TV, a 1-kW electric resistance heater, and a 50-W fan. During a cold winter day,it is observed that the refrigerator, the TV, the fan, and the electric resistance heater are running continuously but the air temperature in the room remains constant. The rate of heat loss from the room that day is
Efficiency of Carnot engine is given as 80%. If the cycle direction is reversed, what will be the value of COP of reversed Carnotcycle
An adiabatic heat exchangeris used to heat cold water at $$15^\circ$$ C entering at a rate of 5 kg/s by hot air at $$90^\circ$$ C entering also at rate of 5 kg/s If the exit temperature of hot air is $$20^\circ$$ C, the exit temperature of cold water is
For given combined radiative and convective heat transfer coefficient ‘h;’ and given thermal conductivity kCritical thickness of insulation for cylinder and sphere is given as
A spherical thermocouple junction of diameter 0.706 mm is to be used for the measurement of temperature of a gas streaim. The convective heat transfer co-efficient on the bead surface is 400 W/m$$^2$$K. Thermo-physical properties of thermocouple material are k = 20 W/mK , C = 400 J/kg K and r = 8500 kg/m$$^3$$ . If the thermocouple initially at $$30^\circ$$ C is placed in a hot stream of $$300^\circ$$ C, the time taken by the bead to reach $$298^\circ$$ C, is
Twoinsulating materials of thermal conductivity K and 2K are available for Jagging a pipe carrying a hotfluid. If the radial thickness of each material is the same.
