Write and simplify the energy balance for the next process, and
indicate if the terms of heat and work other than zero are positive
or negative.
a) A tray filled with water at 20 ° C is placed in the freezer. The
water turns to ice at -5 ° C.
b) The steam enters a rotating turbine and rotates an axis
connected to a generator. The steam inlet and outlet ports are at
the same height. Some of the energy is transferred to the
surroundings as heat.
c) A chemical reaction is carried out in a rigid, closed and
adiabatic container.
Write and simplify the energy balance for the next process, and indicate if the terms of...
2. Write and simplify the closed-system energy balance for each of the following processes, and state whether heat and work terms positive or negative or zero. Begin by defining the are system. Indicate why each term in the energy balance is neglected. The contents of an agitated, sealed flask are heated from 25°C to 80 °C.. a. b. A chemical reaction takes place in a closed adiabatic (perfectly insulated) rigid container. Repeat part (b), only suppose that the reactor is...
In a regenerative ideal Rankine cycle, hot water steam enters the turbine at 10 MPa and 480°C. condenser inlet pressure is 10 kPa. Some steam is taken from the turbine at a pressure of 0.7 MPa, feeds a Closed Feed water heater and is sent to the condenser as a saturated liquid at a pressure of 0.7 MPa at the outlet. The other outlet (cold) is at a pressure of 10 MPa and a saturation temperature of 0.7 MPa. According...
An adiabatic heat exchanger is one for which no heat is exchanged with the surroundings. All of the heat lost by the hot stream is transferred to the cold stream in this adiabatic process. In a proposed process, propane gas enters a continuous adiabatic heat exchanger at 45 °C and 265 kPa and exits at 255 °C. Superheated steam at 300 °C and 7.0 bar enters the exchanger flowing countercurrently to the propane and exits as a saturated liquid at...
Propane gas enters a continuous adiabatic heat exchanger 240°C. Superheated steam at 300 C and 5 bar enters the exchanger flowing countercurrently to the propane and exits as a saturated liquid at the same pressure at 40 C and 250 kPa and exits at Taking flow chart. Include both mass and volumes on your inlet and outlet streams. b. Calculate the specific enthalpy values for the inlet and outlet streams. c. Use an energy balance to calculate the required mass...
Both simple Rankine and Brayton cycles produce a net power of
200MW. Air enters the compressor at 100kPa, 25°C. The compressor
pressure ratio is 12.0, and the turbine inlet temperature is
1127°C. The turbine and compressor each have isentropic
efficiencies of 90.0%. Heat addition is from a thermal reservoir
with a temperature of 1127°C. Heat rejection is to a thermal
reservoir at an ambient temperature of 25°C. The HRSG is a set of
large heat exchangers having, on one side,...
A cogeneration plant is similar to a power plant, but some of the thermal energy in the working fluid is used for process heat (for example heating buildings, steel making, or oil refining). An ideal reheat Rankine cycle with regeneration is modified to a cogeneration plant by adding a process heater as shown in the figure below. The process heater acts as a heat removal step where the enthalpy of the steam is reduced by the heat output (qprocess=h7-h3). The...
5-30 Air enters an adiabatic nozzle steadily at 300 kPa, 200°C, and 30 m/s and leaves at 100 kPa and 180 m/s. The inlet area of the nozzle is 80 cm². Determine (a) the mass flow rate through the nozzle, (b) the exit temperature of the air, and (c) the exit area of the nozzle. Answers: (a) 0.5304 kg/s, (b) 184.6°C, (c) 38.7 cm P = 300 kPa T, = 200°C Vi = 30 m/s A = 80 cm AIR...
Problem 1: This is textbook problem 4.51 (page 224) Steam at 1800 lbf/in2 and 1100 °F enters a turbine operating at steady state. As shown in the Figure, 20% of the entering mass flow is extracted at 600 lbf/in2 and 500 °F. The rest of the steam exits as a saturated vapor at 1 lbf/in2 . The turbine develops a power output of 6.8×106 Btu/h. Heat transfer from the turbine to the surroundings occurs at a rate of 5×104 Btu/h....
(a) Thermal energy is supplied continuously to a material initially in the solid state till it reaches well into the gaseous state. With the help of a schematic diagram discuss the change in temperature with the addition of thermal energy in the form of heat. 9 marks) (b) For a thermodynamic system explain what is meant by isothermal process, adiabatic process, and cyclic process. If the system consists of an ideal gas, state the relationship between internal energy, heat and...
Question B3 (25 Marks Write down a mathematical expression for the First Law of Thermodynamics as applied to steady state, steady flow process, explaining clearly the notation and sign conventions used. (5 marks) Consider steady state, steady flow of steam through a turbine used for electricity generation. You may assume that the process is adiabatic. The steam inlet and exit conditions are; Inlet Exit 15.0 0.01 Pressure (MPa) TemperatureC Velocity (m/s 500 40 80 Fraction 0.92 P, 15.0 MPa T,-500C...