Thermodynamics: First Law Applied to Flow Processes
40 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the mathematical statement of the first law of thermodynamics?

  • dQ = dW (correct)
  • dQ + dW = 0
  • dQ - dW = 0
  • dU = dQ + dW

    • What is the corollary to the first law of thermodynamics that states that there exists a property of a closed system?

  • Corollary 1 (correct)
  • Corollary 2
  • The first law of thermodynamics
  • Corollary 3

    • What is the term for the total energy of a system that includes internal energy, kinetic energy, potential energy, and more?

  • Electrical energy
  • Internal energy
  • Total energy (correct)
  • Kinetic energy

    • What is a hypothetical machine that violates the first law of thermodynamics by creating energy?

    <p>Perpetual Motion Machine of First Kind</p> Signup and view all the answers

    What is the characteristic of a system where heat and work interactions are absent?

    <p>Isolated System</p> Signup and view all the answers

    What is the significance of the equation dU = dQ - dW?

    <p>It shows that energy can be transferred from one form to another</p> Signup and view all the answers

    What is the fundamental principle stated by the first law of thermodynamics?

    <p>Energy is neither created nor destroyed</p> Signup and view all the answers

    What is the result of the cyclic integral of heat added and the integral of work done during a thermodynamic cycle?

    <p>dQ - dW = 0</p> Signup and view all the answers

    What is the consequence of the first law of thermodynamics for the universe as a whole?

    <p>The total energy of the universe is constant</p> Signup and view all the answers

    What is the name of the machine that violates the first law of thermodynamics by producing useful work without any source?

    <p>Perpetual Motion Machine of First Kind</p> Signup and view all the answers

    What is the fundamental principle that all processes in the universe comply with?

    <p>Both the first and second laws of thermodynamics</p> Signup and view all the answers

    What is the consequence of an electric heater that consumes 1KW of electricity?

    <p>It can produce less than 1KW of heat</p> Signup and view all the answers

    What type of flow is characterized by a constant rate of fluid flow through a machine or apparatus?

    <p>Steady flow</p> Signup and view all the answers

    What is the assumption made in the system analysis of the steady flow energy equation?

    <p>The mass flow rate remains constant</p> Signup and view all the answers

    What is the term for the energy associated with the motion of a fluid?

    <p>Kinetic energy</p> Signup and view all the answers

    What is the equation that relates the energy changes between the inlet and outlet of a control volume?

    <p>h1 + KE1 + PE1 = h2 + KE2 + PE2 + E/m</p> Signup and view all the answers

    What is the term for the energy required to move a fluid in and out of a control volume?

    <p>Flow work</p> Signup and view all the answers

    What is the formula for work done by a piston in moving a unit mass of fluid?

    <p>Work done = Force × Displacement</p> Signup and view all the answers

    What is the consequence of an open system with no variation of flow of mass or energy with time?

    <p>Steady flow</p> Signup and view all the answers

    What is the term for the energy lost due to heat transfer, friction, etc.?

    <p>Energy loss</p> Signup and view all the answers

    What is the unit of pressure in the flow work or flow energy equation?

    <p>Pa</p> Signup and view all the answers

    What is the purpose of a nozzle in a fluid flow system?

    <p>To convert thermal energy to kinetic energy</p> Signup and view all the answers

    What is the equation for the work output of a turbine?

    <p>W = (m × (h1 - h2)) + (V1² - V2²) / 2 + (Z1 - Z2)</p> Signup and view all the answers

    What is the purpose of a compressor in a fluid flow system?

    <p>To increase the pressure of a fluid while decreasing its velocity</p> Signup and view all the answers

    What is the equation for the work input required to compress a fluid in a compressor?

    <p>W = (m × (h2 - h1)) + (V2² - V1²) / 2 + (Z2 - Z1)</p> Signup and view all the answers

    What is the purpose of a heat exchanger in a fluid flow system?

    <p>To transfer heat energy from one fluid to another</p> Signup and view all the answers

    What is the equation for the heat transfer process in a heat exchanger?

    <p>m1 (h1 - h2) = m2 (h3 - h4)</p> Signup and view all the answers

    What is the purpose of a throttle valve in a fluid flow system?

    <p>To restrict fluid flow, reducing pressure and temperature</p> Signup and view all the answers

    What is the unit of flow work or flow energy?

    <p>J/kg</p> Signup and view all the answers

    What is the application of the steady flow energy equation in nozzles?

    <p>To analyze the relationship between the inlet and outlet conditions</p> Signup and view all the answers

    What does the SFEE apply to in the case of a throttle valve?

    <p>The conversion of thermal energy to kinetic energy</p> Signup and view all the answers

    What is the purpose of a boiler in a steam power plant?

    <p>To generate steam by heating water</p> Signup and view all the answers

    What is the purpose of a condenser in a steam power plant?

    <p>To condense steam back into liquid water</p> Signup and view all the answers

    What is the SFEE equation for a pump?

    <p>h_1 + rac{p_1}{?g} + rac{V_1^2}{2g} + z_1 = h_2 + rac{p_2}{?g} + rac{V_2^2}{2g} + z_2</p> Signup and view all the answers

    What is the purpose of the SFEE in a pump?

    <p>All of the above</p> Signup and view all the answers

    What is the equation for flow work during steady flow processes?

    <p>W_flow = p_1V_1 - p_2V_2</p> Signup and view all the answers

    What is the equation for external heat transfer during steady flow processes?

    <p>Q_external = m × cp × (T2 - T1)</p> Signup and view all the answers

    What is the total work done during a steady flow process?

    <p>W_total = W_flow + W_shaft + W_internal</p> Signup and view all the answers

    What is the total heat transfer during a steady flow process?

    <p>Q_total = Q_external + Q_internal</p> Signup and view all the answers

    What is the purpose of the SFEE in a boiler?

    <p>To determine the energy added to the fluid by the boiler</p> Signup and view all the answers

    Study Notes

    First Law of Thermodynamics

    • The first law states that energy is neither created nor destroyed, but can be converted from one form to another.
    • The total energy of the universe is a constant.

    Corollaries to the First Law

    • There exists a property of a closed system called internal energy (U), which changes by the difference between heat supplied and work done.
    • For an isolated system, energy is constant, and neither heat nor work interactions occur.
    • It is impossible to create a perpetual motion machine of the first kind, which would produce useful work without any energy input.

    Steady Flow Energy Equation (SFEE)

    • The SFEE is a fundamental equation that relates the energy changes between the inlet and outlet of a control volume.
    • The SFEE accounts for energy losses due to heat transfer, friction, and other interactions.
    • The SFEE is written as: m (h1 + KE1 + PE1) = m (h2 + KE2 + PE2) + E

    Applications of SFEE

    Nozzles

    • SFEE helps understand the relationship between inlet and outlet conditions.
    • The equation reduces to: h1 + KE1 = h2 + KE2, showing a conversion of thermal energy to kinetic energy.

    Diffusers

    • SFEE helps understand the relationship between inlet and outlet conditions.
    • The equation reduces to: h1 + KE1 = h2 + KE2, showing a conversion of kinetic energy to thermal energy.

    Turbines

    • SFEE helps design and optimize turbine performance.
    • The equation is used to determine the work output (W) of a turbine.

    Compressors

    • SFEE is essential for designing and optimizing compressor performance.
    • The equation is used to determine the work input (W) required to compress a fluid.

    Heat Exchangers

    • SFEE helps analyze the heat transfer process.
    • The equation is: m1 (h1 - h2) = m2 (h3 - h4)

    Throttle Valve

    • SFEE applies to the throttle valve, showing a conversion of thermal energy to kinetic energy.

    Boiler

    • SFEE helps analyze the energy transfer in a boiler.
    • The equation is: m (h2 - h1) = Q

    Condenser

    • SFEE applies to the condenser, showing a conversion of thermal energy to kinetic energy.

    Pump

    • SFEE helps analyze the energy transfer in a pump.
    • The equation is: h1 + p1/ρg + V1²/2g + z1 = h2 + p2/ρg + V2²/2g + z2

    Work Done During Steady Flow Processes

    • Work done during steady flow processes can be categorized into three types: flow work, shaft work, and internal work.
    • The total work done is the sum of these three types of work.

    Heat Transfer During Steady Flow Processes

    • Heat transfer can be categorized into two types: external heat transfer and internal heat transfer.
    • The total heat transfer is the sum of external and internal heat transfer.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Description

    This quiz covers the application of the First Law of Thermodynamics to flow processes, including thermodynamic cycles and internal energy. It explores the relationships between heat, work, and energy.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser