Name: venturi meter flow rate from pressure
Uploaded: 2026-01-30T03:08:31.000Z
Duration: 1 min 16 s
Channel: JoVE

Um medidor Venturi é instalado em um sistema de esgoto para medir a vazão de águas residuais. Se a vazão for conhecida e os efeitos viscosos forem insignificantes, qual é a diferença de pressão indicada pelo manômetro conectado ao medidor de vazão?
Primeiro, calcule as áreas da seção transversal do tubo e da garganta usando seus respectivos diâmetros.
Em seguida, usando a equação de continuidade, determine as velocidades em ambas as seções com base na vazão fornecida.
Como a área e a velocidade estão inversamente relacionadas, as águas residuais aceleram à medida que se movem do tubo de maior diâmetro para a garganta menor.
Em seguida, aplique a equação de Bernoulli, que relaciona a diferença de pressão entre dois pontos do fluxo com a mudança na velocidade.
Esta equação mostra que, à medida que a velocidade aumenta quando a água se move do tubo maior para a garganta menor, haverá uma queda de pressão correspondente.
Finalmente, calcule a diferença de pressão entre o tubo e a garganta substituindo as velocidades na equação de Bernoulli.
O manômetro conectado ao medidor de vazão indicará a diferença de pressão final.

equação de bernoulli - resolução de problemas

Um medidor Venturi é essencial para medir taxas de fluxo de fluidos em tubulações. Ele utiliza a relação entre velocidade e pressão do fluido descrita pela equação de Bernoulli. Quando instalado em um sistema de esgoto, o medidor Venturi determina com precisão a taxa de fluxo de águas residuais medindo as diferenças de pressão.

O primeiro passo é calcular as áreas da seção transversal do tubo e da garganta Venturi para analisar a diferença de pressão indicada pelo manômetro. Em seguida, aplica-se a equação da continuidade, que afirma que a taxa de fluxo volumétrico (Q) permanece constante ao longo da tubulação para um fluido incompressível:

<img alt="Equation 1" src="/files/ftp_upload/18035/18035_Equation_1.svg" style="text-align: center; height: 12px;">


A_1 e A_2 são as áreas transversais do tubo e da garganta, e V_1 e V_2 são as velocidades do fluido nessas seções. Ao reorganizar a equação, a velocidade na garganta pode ser expressa como:

<img alt="Equation 2" src="/files/ftp_upload/18035/18035_Equation_2.svg" style="text-align: center; height: 30px;">


Assim, as velocidades V_1 e V_2 podem ser calculadas para uma dada vazão.

A equação de Bernoulli relaciona pressão e velocidade em um fluido ideal, dada por:

<img alt="Equation 3" src="/files/ftp_upload/18035/18035_Equation_3.svg" style="text-align: center; height: 27px;">

Aqui, P_1 e P_2 são as pressões no tubo e na garganta e ⍴ é a densidade do fluido. A diferença de pressão (P_1 - P_2) pode ser calculada substituindo as velocidades V_1 e V_2 nesta equação. Esta queda de pressão (ΔP), indicada pelo manômetro, reflete o aumento na velocidade conforme a água residual flui através da garganta mais estreita, consistente com a conservação de energia.

Equação de Bernoulli - Resolução de Problemas

Um medidor Venturi é instalado em um sistema de esgoto para medir a vazão de águas residuais. Se a vazão for conhecida e os efeitos viscosos forem insignificantes, o que é ...

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Bernoulli's Equation: Problem Solving

venturi meter flow rate from pressure

A Venturi meter measures fluid flow rate in a pipeline by using pressure changes and Bernoulli's equation. In a sewage system, it can be used to determine wastewater flow rate by reading the pressure difference across the meter. The narrowed throat makes the fluid speed up, and that change in speed is linked to pressure drop.

The first step is to find the cross-sectional areas of the pipe and the Venturi throat. These areas are needed to interpret the pressure difference shown on the pressure gauge. Next, the continuity equation is applied. For an incompressible fluid, the volumetric flow rate Q stays constant, and the pipe and throat areas are written as A1 and A2 with velocities V1 and V2.

From the continuity equation, the throat velocity can be rearranged and calculated from the flow rate. Once V1 and V2 are known, Bernoulli's equation is used to relate pressure and velocity in an ideal fluid. With the fluid density included, the pressures P1 and P2 in the pipe and throat can be compared to find the pressure difference.

Substituting the velocities into Bernoulli's equation gives the pressure drop, ΔP. That pressure drop is the value indicated by the pressure gauge. It reflects the increase in fluid speed as wastewater moves through the narrower throat, which follows energy conservation.

Venturi Meter Flow Rate from Pressure

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bernoulli's equation: problem solving

A Venturi meter measures fluid flow rate in a pipeline by using pressure changes and Bernoulli's equation. In a sewage system, it can be used to determine wastewater flow rate by reading the pressure difference across the meter. The narrowed throat makes the fluid speed up, and that change in speed is linked to pressure drop. The first step is to find the cross-sectional areas of the pipe and the Venturi throat. These areas are needed to interpret the pressure difference shown on the pressure...

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key terms and concepts

See how a Venturi meter uses continuity and Bernoulli's equation to turn pressure differences into wastewater flow rate in a sewage system.

Venturi Meter Flow Rate from 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.

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Venturi Meter Flow Rate from Pressure

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