Name: fire extinguisher nozzle flow and pressure
Uploaded: 2025-02-13T15:43:18.000Z
Duration: 1 min 12 s
Channel: JoVE

تستخدم طفاية الحريق الماء المضغوط لتوليد تيار قوي عبر فوهة.
يتم تخزين الماء بالداخل عند ضغط أعلى بكثير من الغلاف الجوي المحيط ، مما يجبر الماء على التدفق عند تنشيط المطفأة.
يتم تطبيق معادلات ديناميكيات الموائع لتحديد مدى سرعة خروج الماء من الفوهة ومقدار طرده بمرور الوقت.
تتضمن الخطوة الأولى فهم فرق الضغط بين الجزء الداخلي من الطفاية والضغط خارج الفوهة.
يقود فرق الضغط هذا حركة الماء. من خلال تطبيق معادلة برنولي ، التي تربط الضغط والسرعة ، يتم حساب سرعة الماء عند خروجه من الفوهة.
يتسبب قطر الفوهة الأصغر في تسارع الماء أثناء مغادرته ، مما يحول الضغط إلى سرعة.
بعد حساب سرعة الخروج ، يتم تحديد معدل التدفق. يتم حساب معدل التدفق باستخدام معادلة الاستمرارية ، والتي تضمن أن كمية المياه المتدفقة عبر الفوهة متسقة.
يتم حساب معدل التدفق بضرب سرعة الماء في مساحة المقطع العرضي للفوهة.

مثال التصميم: التدفق عبرمطفأة الحريق.

Design Example: Flow Through a Fire Extinguisher

<div style="direction:rtl">تعتمد مطفأة الحريق التي تستخدم الماء المضغوط على مبادئ ديناميكا الموائع في اطلاق تيار مياه عالي السرعة قادر على إخماد النيران. يتم تخزين الماء عند ضغط أعلى بكثير داخل مطفأة الحريق مقارنة بالضغط الجوي المحيط. يجبر فرق الضغط هذا الماء على التدفق بسرعة عند فتح مطفأة الحريق، ويمكن فهم سلوك الماء عند خروجه من الفوهة باستخدام المعادلات الأساسية لديناميكيات الموائع. يكمن مفتاح فهم كيفية تسارع الماء في فرق الضغط بين الضغط داخل مطفأة الحريق ووالضغط الجوي خارجها. تٌستخدم معادلة برنولي، التي تربط بين الضغط والسرعة، في حساب سرعة خروج المياه من الفوهة. <img alt="Equation 1" src="/files/ftp_upload/18047/18047_Equation_1.svg" style="text-align: center; height: 45px;"> وفقًا لهذا المبدأ، ومع انخفاض الضغط، تزداد سرعة التدفق. وهذا يعني أن الضغط العالي داخل مطفأة الحريق يتحول إلى سرعة تدفق للماء عند خروجه. مع اقتراب الماء من الفوهة، يعمل انخفاض قطر الفوهة على تسريع التدفق بشكل أكبر، مما يحول طاقة الضغط إلى طاقة حركية. بعد تحديد سرعة خروج المياه، يتم حساب معدل التدفق، أو حجم الماء المتدفق في وحدة الزمن. يتم الحساب باستخدام معادلة الاستمرارية، التي تضمن ثبات تدفق المياه عبر النظام. معدل التدفق هو حاصل ضرب سرعة الماء في مساحة المقطع العرضي للفوهة. <img alt="Equation 2" src="/files/ftp_upload/18047/18047_Equation_2.svg" style="text-align: center; height: 40px;"> نظرًا لصغر قطر الفوهة ، فأن الماء يتدفق بسرعة عالية، مما يوفر تيارًا ثابتًا وقويًا ضروريًا لإخماد الحرائق. من خلال تطبيق هذه المبادئ، يمكن تحسين أداء مطفأة الحريق لضمان تشغيلها بفعالية.</div>

تستخدم طفاية الحريق الماء المضغوط لتوليد تيار قوي عبر فوهة.
يتم تخزين الماء بالداخل عند ضغط أعلى بكثير من ...

design-example-flow-through-a-fire-extinguisher

Education

JoVE Core

Civil Engineering

الهندسة المدنية

Unit 1

الوحدة الأولى

Fluid Kinematics

كينماتيكا السوائل

KEY TERMS AND CONCEPTS

المصطلحات والمفاهيم الأساسية

fire extinguisher nozzle flow and pressure

A pressurized water fire extinguisher uses fluid dynamics to create a fast stream of water. The water is stored at a much higher pressure inside the extinguisher than the surrounding air. When the extinguisher is activated, that pressure difference forces water to flow out quickly.

Bernoulli's equation helps predict the exit speed of the water. This equation links pressure and velocity. As pressure drops, velocity increases. In the extinguisher, the high internal pressure is converted into the water's speed as it leaves the nozzle.

The nozzle also plays an important role because its diameter becomes smaller near the exit. A smaller opening increases the flow speed even more. This turns pressure energy into kinetic energy, which is the energy of motion.

After the exit velocity is found, the flow rate can be calculated. Flow rate is the volume of water expelled each second. The continuity equation is used to keep track of how much water moves through the system, and the flow rate equals the water speed times the nozzle's cross-sectional area. Because the nozzle is small, the water comes out at high velocity and forms a strong, steady stream for fire suppression.

Fire Extinguisher Nozzle Flow and Pressure

fire-extinguisher-nozzle-flow-and-pressure

eulerian and lagrangian flow descriptions

eulerian-and-lagrangian-flow-descriptions

Tracking Fluid Motion in Space and Time

Fluid flow can be described with the Eulerian and Lagrangian methods. These two approaches give different views of the same moving fluid. They are useful in science and engineering because the best method depends on the problem being studied. The Eulerian method looks at fixed points in space. At each location, it measures fluid properties such as velocity, pressure, and temperature as the fluid moves past. This stationary view is useful when studying how a fluid interacts with a solid object.

introduction to types of flows

Flow Patterns by Direction and Time

Fluid flow can be grouped by direction and by how it changes over time. The simplest case is one-dimensional flow. In this type, properties such as velocity and pressure change along only one axis. Water moving through a straight pipe is a common example, because changes in other directions are very small. Two-dimensional flow changes in two directions. It varies in both length and height, so the analysis is more complex than one-dimensional flow. Air moving over a flat surface, such as a...

streamlines, streaklines, and pathlines

Tracing Fluid Motion: Three Flow Paths

Streamlines, streaklines, and pathlines are three ways to describe fluid motion. Each one shows flow from a different angle. Together, they help students compare how a fluid moves in steady and unsteady flow. A streamline is a line that stays tangent to the fluid’s velocity vector at each point. That means the fluid velocity points along the streamline. Streamlines give an instant picture of the flow field, so they are useful for showing the overall direction of flow in a fluid system. In...

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Tracking Fluid Through Space or Mass

Fluid analysis often uses two linked ideas: the control volume approach and the system approach. Both help describe mass, energy, and momentum transfer, but they focus on different things. One follows a region in space. The other follows a fixed mass of fluid over time. The control volume approach looks at a stationary area in space through which fluid moves. That area is bounded by a control surface, which is the outer edge of the region. A pipe with water flowing through it is a clear...

velocity and acceleration in steady and unsteady flow

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How Flow Changes Affect Particle Motion

Velocity and acceleration help describe how a fluid particle moves in steady and unsteady flow. A fluid particle follows a pathline, and its velocity depends on both position and time. Acceleration is found by differentiating velocity with respect to time, so it shows how the particle’s motion changes. In a flow field, acceleration can be written using three perpendicular components. These components show how velocity changes over time in different spatial directions. This gives a general way...

reynolds transport theorem

Reynolds Transport and Control Volumes

Reynolds transport theorem links a fluid system to a control volume. It helps explain how the time rate of change of a property can be tracked in fluid dynamics. The theorem uses extensive properties, such as mass, velocity, acceleration, temperature, and momentum. These properties depend on the size of the system. Their intensive forms are the values per unit mass. The total amount of an extensive property in a system at any instant is the sum of the amounts carried by each tiny fluid...

design example: flow through a fire extinguisher

A pressurized water fire extinguisher uses fluid dynamics to create a fast stream of water. The water is stored at a much higher pressure inside the extinguisher than the surrounding air. When the extinguisher is activated, that pressure difference forces water to flow out quickly. Bernoulli's equation helps predict the exit speed of the water. This equation links pressure and velocity. As pressure drops, velocity increases. In the extinguisher, the high internal pressure is converted into the...

key terms and concepts

Explore how pressure, Bernoulli's equation, and nozzle size control the water speed and flow rate in a pressurized fire extinguisher.

Fire Extinguisher Nozzle Flow and Pressure | JoVE K12

JoVE Core Civil Engineering provides a foundational exploration of essential construction materials in civil engineering, focusing on bricks, stones, steel, wood, and concrete through easy-to-understand animated videos. This collection covers the properties, manufacturing processes, and practical applications of these materials. Additionally, the accompanied science-in-action videos demonstrate the research experiments performed in laboratories.

Fire Extinguisher Nozzle Flow and Pressure

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