Question

Initially (state 1) a well-insulated rigid tank contains 20 kg
of a saturated liquid-vapor mixture of water at 100 kPa and half of
the mass is in the liquid phase. An electric resistance heater
placed in the tank is now turned on and kept on until all the
liquid in the tank is vaporized (state 2). Determine (a) the
initial specific volume in m^{3}/kg, (b) the final specific
entropy in kJ/kg.K and (c) change of entropy in kJ/K.

Answer #1

Initially (state 1) a well-insulated rigid tank contains 20 kg
of a saturated liquid-vapor mixture of water at 100 kPa and half of
the mass is in the liquid phase. An electric resistance heater
placed in the tank is now turned on and kept on until all the
liquid in the tank is vaporized (state 2). Determine (a) the
initial specific volume in m3/kg, (b) the final specific
entropy in kJ/kg.K and (c) change of entropy in kJ/K.

A well-insulated rigid tank contains 6 kg of saturated liquid
vapor mixture of water at 150 kPa. Initially, half of the mass is
in liquid phase. An electric resistance heater placed in the tank
is then turned on and kept on until all the liquid is vaporized.
Determine the electrical work (Wel) in MJ

A well-insulated rigid tank contains 5-kg of a saturated
liquid-vapor mixture of water at 100 kPa. Initially, three-quarters
of the mass is in the liquid phase. An electric heater with a power
rating of 880 W is placed in the tank. Determine how long it will
take to vaporize all the liquid in the tank. Show the process on a
T-v diagram with respect to saturation lines.

A 0.1-m3 rigid tank contains saturated liquid-vapor mixture of
water, initially at 150 kPa and 52 percent quality. Heat is now
transferred to the tank until the system becomes superheated vapor
and the pressure reaches 300 kPa. Determine (a) the total mass of
the mixture in the tank and (b) the amount of heat transferred.

An initially empty, well insulated, rigid tank with a volume of
2 m3 is fitted with a mixing device. The tank has two inlets and
zero outlets. One inlet is water at 1 MPa and 600◦C while the other
is saturated liquid water. Both enter the tank slowly. If the
amount of work done by the mixing device is 300 kJ, what must the
temperature of the saturated liquid water be if the same mass is
added through both inlets...

3. A two-phase liquid-vapor mixture of water, initially at 1.0
MPa with a quality of 71.1436%, is contained in a rigid,
well-insulated tank. The mass of H2O is 2 kg. An electric
resistance heater in the tank transfers energy (heat) to the water
at a constant rate of 80 W. Determine
(a) the time, in hour, when the temperature in the tank reaches
350oC, and
(b) the final pressure, in MPa.

system, a rigid tank, contains mixture of saturated water vapor
and saturated liquid at 90 oC. Total mass is 1.5 kg. quality is
0,34. system is heated untill all liquid is converted into vapor.
how much heat is transferred to the syste, show this process in
P-v-diagram

Water of mass 2 kg in a closed, rigid tank is initially in the
form of a twophase liquid-vapor mixture. The initial temperature is
50° C. The mixture is heated until the tank contains only saturated
vapor at 110° C.
(i) Find the initial pressure, in kPa.
(ii) Find the work for the process, in kJ.
(iii) Find the heat transfer for the process, in kJ.

Q3. A tank with rigid walls and a volume of
0.05 m3 initially has a two-phase liquid- vapor mixture of ammonia
at a pressure of 4 bar and a quality of 10%. The tank is then
heated such that the pressure is kept constant through a
pressure-regulating valve that allows saturated vapor to escape.
The heating continues until the quality of the mixture in the tank
is 40%. Assume kinetic and potential energy changes are
insignificant. Determine:
(i) The final...

A 50 kg copper block initially at 350 oC is quenched in a
closed, rigid insulated tank containing 120 L of liquid water at 25
oC. Specific heat of copper, Cc = 385 J/(kgK), specific heat of
liquid water, Cw = 4180J/(kgK). (i) Calculate the entropy change
(kJ/K) of copper block. (ii) Determine the entropy change (kJ/K) of
liquid water.

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