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

Um extintor de incêndio usa água pressurizada para gerar um fluxo poderoso através de um bico.
A água no interior é armazenada a uma pressão muito mais alta do que a atmosfera circundante, forçando a água a fluir quando o extintor é ativado.
As equações de dinâmica de fluidos são aplicadas para determinar a rapidez com que a água sai do bico e quanto é expelido ao longo do tempo.
O primeiro passo envolve entender a diferença de pressão entre o interior do extintor e a pressão fora do bico.
Essa diferença de pressão impulsiona o movimento da água. Aplicando a equação de Bernoulli, que relaciona pressão e velocidade, calcula-se a velocidade da água ao sair do bico.
O diâmetro menor do bico faz com que a água acelere à medida que sai, transformando a pressão em velocidade.
Depois de calcular a velocidade de saída, a taxa de fluxo é determinada. A vazão é calculada usando a equação de continuidade, que garante que a quantidade de água que flui pelo bico seja consistente.
A vazão é calculada multiplicando a velocidade da água pela área da seção transversal do bico.

exemplo de design: fluxo através de um extintor de incêndio

Design Example: Flow Through a Fire Extinguisher

Um extintor de incêndio que usa água pressurizada depende de princípios de dinâmica de fluidos para gerar um fluxo de alta velocidade capaz de suprimir chamas. A água é armazenada a uma pressão muito maior dentro do extintor do que a atmosfera ao redor. Essa diferença de pressão força a água a fluir rapidamente quando o extintor é ativado, e o comportamento da água ao sair do bico pode ser compreendido usando equações fundamentais da dinâmica de fluidos.

A chave para entender como a água acelera está na diferença de pressão entre o interior do extintor e o ambiente externo. A equação de Bernoulli, que relaciona pressão e velocidade, calcula a rapidez com que a água sairá do bico.

<img alt="Equation 1" src="/files/ftp_upload/18047/18047_Equation_1.svg" style="text-align: center; height: 45px;">

De acordo com esse princípio, à medida que a pressão diminui, a velocidade aumenta. Isso significa que a alta pressão interna dentro do extintor é convertida na velocidade da água à medida que ela flui para fora. À medida que a água se aproxima do bico, a diminuição do diâmetro do bico acelera ainda mais o fluxo, transformando a energia da pressão em energia cinética.

Após determinar a velocidade de saída da água, a vazão, ou o volume de água expelido ao longo do tempo, é calculado. O cálculo usa a equação de continuidade, garantindo que a água que flui pelo sistema permaneça constante. A vazão é o produto da velocidade da água e da área da seção transversal do bico.

<img alt="Equation 2" src="/files/ftp_upload/18047/18047_Equation_2.svg" style="text-align: center; height: 40px;">

Como o bico tem um diâmetro pequeno, a água é expelida em alta velocidade, fornecendo um fluxo consistente e poderoso necessário para a supressão de incêndio. Ao aplicar esses princípios, o desempenho do extintor pode ser otimizado para garantir uma operação eficaz.

Exemplo de design: fluxo através de um extintor de incêndio

Um extintor de incêndio usa água pressurizada para gerar um fluxo poderoso através de um bico.
A água no interior é armazenada a uma pressão muito mais alta do que a ...

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

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Fluid Kinematics

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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

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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.

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Fire Extinguisher Nozzle Flow and Pressure

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