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

Un contatore Venturi è installato in una rete fognaria per misurare la portata delle acque reflue. Se la portata è nota e gli effetti viscosi sono trascurabili, qual è la differenza di pressione indicata dal manometro collegato al flussometro?
Innanzitutto, calcola le aree della sezione trasversale sia del tubo che della gola utilizzando i rispettivi diametri.
Quindi, utilizzando l'equazione di continuità, determinare le velocità in entrambe le sezioni in base alla portata data.
Poiché l'area e la velocità sono inversamente correlate, le acque reflue accelereranno man mano che si spostano dal tubo di diametro maggiore alla gola più piccola.
Successivamente, applica l'equazione di Bernoulli, che mette in relazione la differenza di pressione tra due punti del flusso con la variazione di velocità.
Questa equazione mostra che all'aumentare della velocità quando l'acqua si sposta dal tubo più grande alla gola più piccola, ci sarà una corrispondente caduta di pressione.
Infine, calcola la differenza di pressione tra il tubo e la gola sostituendo le velocità nell'equazione di Bernoulli.
Il manometro collegato al flussometro indicherà la differenza di pressione finale.

equazione di bernoulli - risoluzione di problemi

Un misuratore Venturi è essenziale per misurare le portate di fluido nelle condotte. Esso utilizza la relazione tra velocità e pressione del fluido, descritta dall'equazione di Bernoulli. Quando installato in un sistema fognario, il misuratore Venturi determina con precisione la portata delle acque reflue, misurando le differenze di pressione.

Il primo passaggio consiste nel calcolare le aree trasversali del tubo e della gola del Venturi, per analizzare la differenza di pressione indicata dal manometro. Successivamente, viene applicata l'equazione di continuità, che afferma che la portata volumetrica (Q) rimane costante lungo la conduttura per un fluido incomprimibile:

<img alt="Equation 1" src="/files/ftp_upload/18035/18035_Equation_1.svg" style="text-align: center; height: 12px;">

A_1 e A_2 sono le aree trasversali del tubo e della gola, mentre V_1 e V_2 sono le velocità del fluido in queste sezioni. Riorganizzando l'equazione, la velocità alla gola può essere espressa come:

<img alt="Equation 2" src="/files/ftp_upload/18035/18035_Equation_2.svg" style="text-align: center; height: 30px;">

Quindi, per una data portata possono essere calcolate le velocità V_1 e V_2.

L'equazione di Bernoulli mette in relazione pressione e velocità in un fluido ideale, data da:

<img alt="Equation 3" src="/files/ftp_upload/18035/18035_Equation_3.svg" style="text-align: center; height: 27px;">

Qui, P_1 e P_2 sono le pressioni nel tubo e nella gola e ⍴ è la densità del fluido. La differenza di pressione (P_1 - P_2) può essere calcolata sostituendo le velocità V_1 e V_2 in questa equazione. Questa caduta di pressione (ΔP), indicata dal manometro, riflette l'aumento di velocità mentre le acque reflue scorrono attraverso la gola più stretta, in linea con il risparmio energetico.

Equazione di Bernoulli - Risoluzione di Problemi

Un contatore Venturi è installato in una rete fognaria per misurare la portata delle acque reflue. Se la portata è nota e gli effetti viscosi sono trascurabili, ciò che è ...

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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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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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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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