Question

Statement (I): Steady flow means that the rates of flow of mass and energy through the control volume are constant.

Statement (II): At the steady-state of a system, any thermodynamic property will have a fixed value at a particular location and will not alter with time.
1. Both Statements (I) and Statement (II) are individually true, and Statement (II) is the correct explanation of Statement (I)
2. Both Statement (I) and Statement (II) are individually true but Statement (II) is NOT the correct explanation of Statement (I)
3. Statement (I) is true, but Statement (II) is false
4. Statement (I) is false, but Statement (II) is true

Answer 1

Correct Answer - Option 1 : Both Statements (I) and Statement (II) are individually true, and Statement (II) is the correct explanation of Statement (I)

Explanation:

Steady-flow Process: 

A steady flow process is a process, where the fluid properties can change from point to point in the control volume but remains the same at any fixed point during the whole process. A steady flow process is characterized by the following:

• No properties within the control volume change with time,

⇒ m_cv = constant, E_cv = constant

• No properties change at the boundaries with time. Thus, the fluid properties at an inlet or exit will remain the same during the whole process. They can be different at different opens.
• The heat and work interactions between a steady-flow system and its surroundings do not change with time.

Mass and Energy Balance for Steady-flow Process,

During a steady-flow process, the total amount of mass contained within a control volume does not change with time. That is,

\( \Rightarrow \frac{{d{m_{system}}}}{{dt}} = 0\) 

⇒ ∑ ṁ_in = ∑ ṁ_out 

⇒ Total mass entering the control volume per unit time will be equal to the total mass leaving the control volume per unit time.

For a steady-flow process,

\(\Rightarrow \frac{{d{E_{system}}}}{{dt}} = 0\) 

⇒ ∑ Ė_in = ∑ Ė_out 

⇒ The rate of net energy transfer by heat, work, and mass at the inlet will be equal to the net rate of net energy transfer by heat, work, and mass at the exit.