For which of the following scenarios is the isothermal flow model most applicable?

Correct answer: Natural gas flowing over several hundreds of meters in a pipeline.

Explanation

The isothermal flow model is best suited for long ducts where the flow is relatively slow, allowing sufficient time for heat transfer with the surroundings to maintain a near-constant temperature.

Other questions

Question 1

What is the fundamental assumption for the model of isothermal flow described in the chapter?

Question 2

In the momentum equation for isothermal flow, -AdP - τ_w * d(A_wetted area) = m_dot * dU, what does the term τ_w represent?

Question 3

How is the hydraulic diameter, DH, defined in the context of isothermal flow?

Question 4

What is the relationship between the Fanning friction factor (f), shear stress (τ_w), density (ρ), and velocity (U)?

Question 5

What is the limiting Mach number for isothermal flow from a mathematical point of view, beyond which the right-hand side of the integrated friction equation becomes negative?

Question 6

In an isothermal flow, what happens to the stagnation temperature as the flow progresses?

Question 7

In the derivation for the dimensionless representation of isothermal flow, what is the relationship between the fractional change in pressure (dP/P) and the fractional change in velocity (dU/U)?

Question 8

For a tube with a Fanning friction factor f = 0.005, a length L = 5000 m, and a diameter D = 0.25 m, what is the value of the dimensionless resistance term 4fL/D?

Question 9

For an isothermal flow, how is the pressure ratio P/P_star related to the Mach number M and the specific heat ratio k?

Question 10

What is the relationship for the velocity ratio U/U_star in a choked isothermal flow as a function of Mach number (M) and specific heat ratio (k)?

Question 12

When expanding the solution for isothermal flow for a small pressure drop, what does the expression 4fL/D approximate to in terms of the pressure drop ratio χ and initial Mach number M1?

Question 13

Why does the core assumption of the isothermal flow model break down for the supersonic branch?

Question 14

A typical value for the Fanning friction coefficient is f = 0.005. For a case where the dimensionless friction term 4fL_max/D is 10, what is the value of L_max/D?

Question 15

According to the relationship dP/P = -[kM^2 / (2 * (1 - kM^2))] * (4f dx/D), what happens to the pressure (P) in a subsonic isothermal flow where M < 1/sqrt(k)?

Question 16

According to the relationship dP/P = -[kM^2 / (2 * (1 - kM^2))] * (4f dx/D), what is the behavior of pressure (P) in a supersonic isothermal flow where M > 1/sqrt(k)?

Question 17

The integration of the separated variables for dimensionless friction from an initial Mach number M to the choking point yields the maximum resistance 4fL_max/D. What is this integrated expression?

Question 18

For incompressible flow, the pressure loss P1 - P2 is given by (4fL/D) * (ρ * U^2 / 2). How is this different from the isothermal flow model?

Question 19

Which equation represents the energy equation for isothermal flow through a control volume where heat transfer occurs?

Question 20

What is the expression for the stagnation temperature ratio T0/T0_star in an isothermal flow?

Question 21

Given a specific heat ratio k=1.4, if the dimensionless resistance 4fL/D for an isothermal flow is 13.9747, what is the corresponding Mach number M?

Question 22

For an isothermal flow with a Mach number of 0.5 and a specific heat ratio of k=1.4, what is the pressure ratio P/P_star?

Question 23

For an isothermal flow with a Mach number of 0.8 and a specific heat ratio of k=1.4, what is the stagnation temperature ratio T0/T0_star?

Question 24

For isothermal flow, what does the differentiation of the mass conservation equation yield in dimensionless form?

Question 25

As a subsonic isothermal flow (M < 1/sqrt(k)) moves down a pipe with friction, what happens to the Mach number?

Question 26

In a subsonic isothermal flow, what happens to the stagnation pressure P0?

Question 27

As a subsonic isothermal flow moves down a pipe, how does the fluid density (ρ) change?

Question 28

The equation 4fL/D = 2 ln(M1) - 1 - (1 - kM2^2)/(kM2^2) is a reduced approximation for a specific scenario. What is this scenario?

Question 29

The stagnation pressure ratio P0/P0_star can be expressed as a function of the static pressure ratio P/P_star and Mach number M. What is this expression?

Question 30

For a large entrance length (large 4fL/D), what is the approximate relationship for the entrance Mach number M1?