How do you calculate valve CV?

How do you calculate valve CV?

Cv by definition is the number of gallons per minute (GPM) a valve will flow with a 1 psi pressure drop across the valve. For example a valve with a Cv of 10 will flow 10 GPM with a 1 psi pressure drop. The formula used to select the valve Cv with the specified differential pressure is: Cv=GPM/((SQ RT(∆P)).

What is the purpose of CV?

Essentially, a CV is designed to summarise all your academic, professional and personal (where relevant) achievements in order to entice or interest a hiring manager when applying for a new job opportunity.

What is CV in gas flow?

Valve Flow Coefficient (Cv) is a valve’s capacity for a liquid or gas to flow through it. It is technically defined as “the volume of water at 60°F (in US gallons) that will flow through a valve per minute with a pressure drop of 1 psi across the valve.”

Why is CP is greater than CV?

When a gas is heated at a constant volume, the work done on the gas increases the internal energy of the system. Cp is greater than the molar specific heat at constant volume Cv because energy must now be supplied not only to raise the temperature of the gas but also for the gas to do work.

What makes a perfect gas?

Perfect gas, also called ideal gas, a gas that conforms, in physical behaviour, to a particular, idealized relation between pressure, volume, and temperature called the general gas law. …

How do you calculate CV for gas?

The volume flow rate for liquids can be calculated by multiplying the fluid velocity times the flow area. Thus, Cv is numerically equal to the number of U.S. gallons of water at 60°F that will flow through the valve in one minute when the pressure differential across the valve is one pound per square inch.

How do you calculate CP?

Cp is an index used to assess the width of the process spread in comparison to the width of the specification. It is calculated by dividing the allowable spread by the actual spread.

What is CV range?

It is often expressed as a percentage, and is defined as the ratio of the standard deviation to the mean (or its absolute value, ). The CV or RSD is widely used in analytical chemistry to express the precision and repeatability of an assay.

What is the value of k for air?


How do you calculate CP of water?

The specific heat capacity of water is 4.18 J/g/°C. We wish to determine the value of Q – the quantity of heat. To do so, we would use the equation Q = m•C•ΔT. The m and the C are known; the ΔT can be determined from the initial and final temperature.

How do you calculate CP and CV?

The specific heat of gas at constant volume in terms of degree of freedom ‘f’ is given as: Cv = (f/2) R. So, we can also say that, Cp/Cv = (1 + 2/f), where f is degree of freedom. Monoatomic gas has only one translational motion, hence three translational degrees of freedom.

What is CP and CV?

The heat capacity at constant pressure CP is greater than the heat capacity at constant volume CV , because when heat is added at constant pressure, the substance expands and work.

What is CP of steam?

Steam Cp=1.8723 kJ/kg. K Cv=1.4108 kJ/kg. K – see steam tables. At IUPAC standard temperature and pressure (0 °C and 101.325 kPa), dry air has a density of 1.2754 kg/m3.

What is the value of CV for water?

What is Cv value? The valve flow coefficient according to the JIS standard, represents the flow capacity in US gallons/minute of 60° F pure water when it is flowing through the valve with a pressure difference of 1 psi at the specified travel (operation range).

What is difference between gas and Vapour?

Vapour is a mixture of two or more different phases at room temperature, these phases are liquid and gaseous phase. Gas usually contains a single thermodynamic state at room temperature. Vapour has a definite shape of the gaseous particles when observed under a microscope. Vapour is not a state of matter, unlike gases.

What is CV of air?

The nominal values used for air at 300 K are CP = 1.00 kJ/kg. K, Cv = 0.718 kJ/kg. K,, and k = 1.4. However they are all functions of temperature, and with the extremely high temperature range experienced in internal combustion and gas turbine engines one can obtain significant errors.

What is C SUBV?

ΔP is the pressure drop across the valve (expressed in psi). In more practical terms, the flow coefficient Cv is the volume (in US gallons) of water at 60 °F that will flow per minute through a valve with a pressure drop of 1 psi across the valve.

Is water vapor a gas?

Water vapor is a critical gas in the atmosphere because it is the gaseous form of water, a building block of life.

How do you calculate flow rate on CV?

Control Valve Sizing

  1. Control Valve Sizing.
  2. When sizing a control valve, the most common approach is to calculate the flow coefficient, Cv which is a measure of the capacity of the valve body and trim.
  3. C = Q/N1 * √ (ρ1/ρ0) / (∆P)
  4. ρ1/ρ0 is the relative density.
  5. Fluid Density: 965.4 kg/m3.
  6. Flow Rate (Q): 360 m3/h.
  7. C = Q/N1 * √ (ρ1/ρ0) / (∆P)

Is air an ideal gas?

Actually there is no “real” gas that is truly an ideal gas. At STP (Standard Temperature and Pressure) air and most pure gasses will behave closely enough to an ideal gas that the ideal gas law can be used. At high temperature and low pressure gasses behave more like an ideal gas.

What is Q MCP ∆ T?

The relationship between heat energy and temperature is different for every material, and the specific heat is a value that describes how they relate. heat energy = (mass of substance)(specific heat)(change in temperature) Q = mc∆T. Q = heat energy (Joules, J)

What is CV for ideal gas?

The molar specific heat capacity of a gas at constant volume (Cv) is the amount of heat required to raise the temperature of 1 mol of the gas by 1 °C at the constant volume. Its value for monatomic ideal gas is 3R/2 and the value for diatomic ideal gas is 5R/2.

What is CV value?

The valve coefficient, Cv, is a number which represents the capability of a valve (or any flow component) to flow a fluid. By definition, a Cv value of one is the Cv required to flow one gallon per minute (gpm) of water at 60′ F with a pressure differential of one psi. Flow is proportional to the value of Cv.

What is CP CV called?

The Cp/Cv ratio is also called the heat capacity ratio. In thermodynamics, the heat capacity ratio is known as the adiabatic index.