Calculate the gas flow rate.

In summary, we are given a stainless steel natural gas pipeline with a length of 180Km and a diameter of 0.4m. The pressure at the start of the pipeline is 4MPa and at the end is 2MPa. Using the given values of density and viscosity for natural gas, we can calculate the kinematic velocity and Reynolds number of the flow. Since the Reynolds number is less than 2100, the flow is considered laminar. By using Moody's diagram and trial and error, we can determine the friction factor and compute the velocity and mass flow rate through the system.
  • #1
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1. Homework Statement

The pressure at the start of a 180Km stainless steel natural gas pipeline is 4MPa and at the end is 2MPa. If the diameter of the pipe is 0.4m, what will be the gas flow rate through the system? (ignore losses other than friction)

(For natural gas, ρ = 40 kg/m^3, μ = 11x10^-6 Pas).

2. Homework Equations

u = q/a

re = (u)(d)/v

hf = p/(density)(g)(Q)

3. The Attempt at a Solution .

Kinematic velocity; \nu=11x10-6/40 = 2.75*10-7

Reynolds number equation; Re = 1x10-6*0.4/2.75*10-7 = 16

Re number < 2100 => flow is laminar

From Moody's diagram, Friction Factor value = 0.002
 
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  • #2
A problem such as this involves a trial and error solution. Guess a velocity at the given upstream pressure of 4MPa . From this, determine the downstream pressure. If the pressure is too high, guess another upstream velocity and recompute the downstream pressure. Repeat the process until computed downstream pressure is 2MPa. Based on the final velocity, compute the mass flow.
 

What is gas flow rate and why is it important?

Gas flow rate is the volume of gas that passes through a specific point in a given time. It is an important measurement in industries such as oil and gas, chemical processing, and power generation. It allows for the optimization of processes, detection of leaks, and monitoring of equipment performance.

How do you calculate gas flow rate?

Gas flow rate can be calculated by dividing the volume of gas (in cubic feet or meters) by the time it took to flow (in seconds or minutes). This can be expressed as Q = V / t, where Q is the gas flow rate, V is the volume, and t is the time.

What are the units of gas flow rate?

The most commonly used unit for gas flow rate is standard cubic feet per minute (SCFM) in the United States, and cubic meters per hour (m3/h) in the metric system. Other units include standard liters per minute (SLPM), standard cubic meters per hour (SCMH), and standard cubic feet per hour (SCFH).

What factors can affect gas flow rate?

Gas flow rate can be affected by factors such as pressure, temperature, viscosity, and density of the gas. Changes in these variables can result in changes in gas flow rate, which should be taken into account during calculations.

What instruments are used to measure gas flow rate?

There are various instruments used to measure gas flow rate, including orifice meters, venturi meters, turbine flow meters, and ultrasonic flow meters. Each instrument has its own advantages and limitations, and the most suitable one should be chosen based on the specific application.

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