/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 72 A large pipe carries steam as a ... [FREE SOLUTION] | 91影视

91影视

Log out

Learning Materials

Features

Discover

Chapter 4: Problem 72

A large pipe carries steam as a two-phase liquid-vapor mixture at \(1.0 \mathrm{MPa}\). A small quantity is withdrawn through a throttling calorimeter, where it undergoes a throttling process to an exit pressure of \(0.1 \mathrm{MPa}\). For what range of exit temperatures, in \({ }^{\circ} \mathrm{C}\), can the calorimeter be used to determine the quality of the steam in the pipe? What is the corresponding range of steam quality values?

Short Answer

Expert verified
Exit temperatures: \textgreater 45.8掳C. Corresponding steam quality range: determined by enthalpy values at pressures 1.0 MPa and 0.1 MPa.

Step by step solution

01

- Understanding the Problem

The goal is to find the range of exit temperatures and corresponding steam quality values for a throttling calorimeter process. Given data: initial pressure of 1.0 MPa and exit pressure of 0.1 MPa.
02

- Determine Saturation Temperatures

Look up the saturation temperatures for water at the given pressures using steam tables. The saturation temperature at 1.0 MPa is approximately 179.9掳C.
03

- Utilize Throttling Process Properties

In a throttling process, enthalpy remains constant. Therefore, the enthalpy of the steam at 1.0 MPa and the initial quality is equal to the enthalpy at 0.1 MPa.
04

- Saturation Temperature at Exit Pressure

To ensure that a two-phase mixture exists at the exit, check the saturation temperature at 0.1 MPa. It's approximately 45.8掳C.
05

- Quality at Exit Pressure Range

For the calorimeter to be useful, the exit temperature should be between the saturation temperature and superheated temperature at 0.1 MPa. Use steam tables to determine the range.
06

- Corresponding Range of Steam Quality Values

Calculate the quality of steam in the pipe by finding the enthalpy at 1.0 MPa for the given temperatures and pressures using interpolation if necessary.
07

- Final Range Calculation

For the saturation range, the exit temperature should be 45.8掳C or higher. Quality values can then be determined from the enthalpy balance at both ends of the range.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Steam Quality
Steam quality, often represented as 'x,' is a measure of the proportion of steam in a liquid-vapor mixture. It's a value between 0 (all liquid) to 1 (all vapor). In practical applications, knowing the steam quality is important for understanding the energy content and efficiency of steam in processes.
For instance, in a throttling calorimeter, steam quality is determined by analyzing the changes in pressure and temperature during the throttling process.
A higher steam quality indicates a higher proportion of vapor in the mixture, which translates to higher energy content per unit mass. Measuring steam quality helps in various engineering and industrial processes where steam's thermal properties are crucial.
Saturation Temperature
Saturation temperature is the temperature at which a liquid boils and turns into vapor at a given pressure. In the context of steam tables, it鈥檚 crucial because it defines the temperature at which liquid water turns into steam at a specific pressure.
For example, at 1.0 MPa, the saturation temperature is approximately 179.9掳C, meaning water will boil and turn into steam at this temperature under this pressure. Understanding saturation temperature is essential when working with steam because processes often depend on precise temperature and pressure conditions.
In a throttling calorimeter, it's important to ensure the steam is in both phases by cross-referencing the saturation temperatures at the initial and exit pressures.
Enthalpy
Enthalpy, represented as 'h,' is a measure of the total energy content in a thermodynamic system, per unit mass. It includes both internal energy and the energy required to make room for the substance (pressure-volume work). Enthalpy is crucial in processes involving heat exchange and phase changes.
In a throttling process, the enthalpy remains constant. This property helps in determining the steam quality by comparing the initial and final states of the steam.
For instance, if steam at 1.0 MPa undergoes throttling to 0.1 MPa, the enthalpy before and after the throttling process remains the same. This constant enthalpy can be used to find the quality of the steam at the exit pressure by using steam tables and known saturation temperatures.
Thus, understanding how to calculate and utilize enthalpy is vital in analyzing and designing systems that involve thermal energy transformations.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

A \(0.5 \mathrm{~m}^{3}\) tank initially contains air at \(300 \mathrm{kPa}, 350 \mathrm{~K}\). Air slowly escapes from the tank until the pressure drops to \(100 \mathrm{kPa}\). The air that remains in the tank undergoes a process described by \(p v^{1.3}=\) constant. For a control volume enclosing the tank, determine the heat transfer, in kJ. Assume ideal gas behavior with constant specific heats.

Air is compressed at steady state from \(1 \mathrm{bar}, 300 \mathrm{~K}\), to 6 bar with a mass flow rate of \(4 \mathrm{~kg} / \mathrm{s}\). Each unit of mass passing from inlet to exit undergoes a process described by \(p v^{1.27}=\) constant. Heat transfer occurs at a rate of \(46.95 \mathrm{~kJ}\) per \(\mathrm{kg}\) of air flowing to cooling water circulating in a water jacket enclosing the compressor. If kinetic and potential energy changes of the air from inlet to exit are negligible, calculate the compressor power, in \(\mathrm{kW}\).

Figure P4.10D provides the schematic of a device for producing a combustible fuel gas from biomass. Owing to petroleum shortages, similar gasifiers were widely used in Europe during the 1940 s war years, including use in tractors, trucks, fishing and ferry boats, and stationary engines. While several types of solid biomass can be employed in current gasifier designs, wood chips are commonly used. Wood chips are introduced at the top of the gasifier unit. Just below this level, the chips react with oxygen in the combustion air to produce charcoal. At the next depth, the charcoal reacts with hot combustion gases from the charcoal-formation stage to produce a fuel gas consisting mainly of hydrogen, carbon monoxide, and nitrogen from the combustion air. The fuel gas is then cooled, filtered, and ducted to the internal combustion engine served by the gasifier. Critically evaluate the suitability of this technology for use today in the event of a prolonged petroleum shortage in your locale. Document your conclusions in a memorandum.

Ammonia enters a heat exchanger operating at steady state as a superheated vapor at 14 bar, \(60^{\circ} \mathrm{C}\), where it is cooled and condensed to saturated liquid at 14 bar. The mass flow rate of the ammonia is \(450 \mathrm{~kg} / \mathrm{h}\). A separate stream of air enters the heat exchanger at \(17^{\circ} \mathrm{C}, 1\) bar and exits at \(42^{\circ} \mathrm{C}, 1\) bar. Ignoring heat transfer from the outside of the heat exchanger and neglecting kinetic and potential energy effects, determine the mass flow rate of the air, in \(\mathrm{kg} / \mathrm{min} .\)

Water is drawn steadily by a pump at a volumetric flow rate of \(0.8 \mathrm{~m}^{3} / \mathrm{min}\) through a pipe with a \(10 \mathrm{~cm}\) diameter inlet. The water is delivered to a tank placed at a height of \(10 \mathrm{~m}\) above the pipe inlet. The water exits through a nozzle having a diameter of \(2.5 \mathrm{~cm}\). Water enters at \(25^{\circ} \mathrm{C}\) and \(1 \mathrm{~atm}\) pressure but there is no significant change in pressure and temperature at exit. Six percent of the power input to the pump is dissipated in the form of heat into the surroundings. Take the value of acceleration due to gravity \((g)\) equal to \(9.8 \mathrm{~m} / \mathrm{s}^{2}\). Determine (a) the velocity of the water at the inlet and exit, and (b) the power required by the pump.
See all solutions

Recommended explanations on Physics Textbooks

Dynamics

Read Explanation

Torque and Rotational Motion

Read Explanation

Linear Momentum

Read Explanation

Circular Motion and Gravitation

Read Explanation

Nuclear Physics

Read Explanation

Turning Points in Physics

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.