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This document discusses the calculation of air density. It defines density and lists its units of measurement. It then provides details on the density of air at sea level, how it decreases with altitude and increases in temperature. It describes two methods for calculating air density: using the ideal gas law accounting for temperature and pressure, and using partial pressure accounting for humidity. Factors that affect air density are identified as altitude, temperature, pressure, humidity and composition. Applications of understanding air density are also outlined.
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Lectures 1 ok
This document provides an overview of fundamental properties of air and water vapor mixtures presented in a lecture by Assistant Lecturer Karrar Al-Mansoori. It defines key terms like dry bulb temperature, wet bulb temperature, humidity, relative humidity, and partial pressure. It also outlines the composition of dry air, gas laws, Dalton's law of partial pressures, saturation vapor pressure, and how to calculate vapor pressure and relative humidity of a moist air mixture. The summary focuses on the essential concepts and terminology introduced in the lecture.
14 fluids
The document discusses key concepts in fluid mechanics including:
1) Phases of matter, density, specific gravity, and pressure in fluids. Pressure increases with depth in a fluid.
2) Pascal's principle states that pressure increases are transmitted undiminished throughout a fluid. This allows hydraulic systems to work.
3) Archimedes' principle explains that the buoyant force on an object equals the weight of fluid displaced. Whether an object floats or sinks depends on its density compared to the fluid.
construction of Psychromtery
The document describes how to construct a psychrometric chart, which is a graphical representation of the thermodynamic properties of moist air. It first defines key terms like dry bulb temperature, wet bulb temperature, dew point temperature, relative humidity, and enthalpy. It then explains how to plot lines on the chart for saturation, constant relative humidity, constant enthalpy, and constant specific volume by calculating moisture content (w) at different dry bulb temperatures using appropriate equations. The psychrometric chart allows analyzing properties of air for applications like HVAC and food processing.
1.7 form 4 pressure
Pressure in liquids is calculated using the equation P = ρgh, where P is pressure, ρ is density, g is gravitational acceleration, and h is height. Atmospheric pressure at sea level is about 100,000 Pa and can also be measured in mercury height, atmospheres, or millibars. Atmospheric pressure is measured using a barometer, such as a mercury barometer that measures the height of a mercury column under atmospheric pressure. A manometer measures pressure differences by the height difference of two liquid columns, with the excess pressure being the actual pressure minus atmospheric pressure.
Humidity control
Humidifier
Terminology : psychometry , absolute humidity , relative humidity , dew point , wet bulb temperature , adiabatic saturation temperature
Dehumidifier
Psychometric chart and its uses
Measurement of humidity
Application of humidity control
vapour pressure
Vapor pressure is the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases at a given temperature. It relates to the evaporation rate of a liquid and is affected by factors like temperature, composition of mixtures, and presence of solids or liquids. Vapor pressure increases non-linearly with temperature and the boiling point of a liquid is reached when its vapor pressure equals atmospheric pressure. It plays an important role in cloud formation through processes like condensation, supersaturation, and Raoult's law governing vapor pressures in mixtures.
Physics fluids - glencoe 13.3
1) Pascal's principle states that pressure is transmitted equally in all directions throughout an enclosed fluid. It explains how hydraulic machines like hydraulic presses are able to multiply applied force.
2) Archimedes' principle states that the buoyant force on an object submerged or partially submerged in a fluid is equal to the weight of the fluid displaced.
3) Bernoulli's principle relates pressure and velocity within a fluid flow and can be used to explain how aircraft wings generate lift and how venturi tubes work. It involves the conservation of energy and mass within a fluid system.
liquid state and its properties
Definite Volume
Not Definite Shape
Molecules Are Much Closer Than Gases
Intermolecular Forces In Between Solids And Gases
properties of liquids
Evaporation
Process Of Changing A Liquid Into A Gas Phase
For example, liquid water conversion into vapor form
Cooling Process
Recommended
Lectures 1 ok
This document provides an overview of fundamental properties of air and water vapor mixtures presented in a lecture by Assistant Lecturer Karrar Al-Mansoori. It defines key terms like dry bulb temperature, wet bulb temperature, humidity, relative humidity, and partial pressure. It also outlines the composition of dry air, gas laws, Dalton's law of partial pressures, saturation vapor pressure, and how to calculate vapor pressure and relative humidity of a moist air mixture. The summary focuses on the essential concepts and terminology introduced in the lecture.
14 fluids
The document discusses key concepts in fluid mechanics including:
1) Phases of matter, density, specific gravity, and pressure in fluids. Pressure increases with depth in a fluid.
2) Pascal's principle states that pressure increases are transmitted undiminished throughout a fluid. This allows hydraulic systems to work.
3) Archimedes' principle explains that the buoyant force on an object equals the weight of fluid displaced. Whether an object floats or sinks depends on its density compared to the fluid.
construction of Psychromtery
The document describes how to construct a psychrometric chart, which is a graphical representation of the thermodynamic properties of moist air. It first defines key terms like dry bulb temperature, wet bulb temperature, dew point temperature, relative humidity, and enthalpy. It then explains how to plot lines on the chart for saturation, constant relative humidity, constant enthalpy, and constant specific volume by calculating moisture content (w) at different dry bulb temperatures using appropriate equations. The psychrometric chart allows analyzing properties of air for applications like HVAC and food processing.
1.7 form 4 pressure
Pressure in liquids is calculated using the equation P = ρgh, where P is pressure, ρ is density, g is gravitational acceleration, and h is height. Atmospheric pressure at sea level is about 100,000 Pa and can also be measured in mercury height, atmospheres, or millibars. Atmospheric pressure is measured using a barometer, such as a mercury barometer that measures the height of a mercury column under atmospheric pressure. A manometer measures pressure differences by the height difference of two liquid columns, with the excess pressure being the actual pressure minus atmospheric pressure.
Humidity control
Humidifier
Terminology : psychometry , absolute humidity , relative humidity , dew point , wet bulb temperature , adiabatic saturation temperature
Dehumidifier
Psychometric chart and its uses
Measurement of humidity
Application of humidity control
vapour pressure
Vapor pressure is the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases at a given temperature. It relates to the evaporation rate of a liquid and is affected by factors like temperature, composition of mixtures, and presence of solids or liquids. Vapor pressure increases non-linearly with temperature and the boiling point of a liquid is reached when its vapor pressure equals atmospheric pressure. It plays an important role in cloud formation through processes like condensation, supersaturation, and Raoult's law governing vapor pressures in mixtures.
Physics fluids - glencoe 13.3
1) Pascal's principle states that pressure is transmitted equally in all directions throughout an enclosed fluid. It explains how hydraulic machines like hydraulic presses are able to multiply applied force.
2) Archimedes' principle states that the buoyant force on an object submerged or partially submerged in a fluid is equal to the weight of the fluid displaced.
3) Bernoulli's principle relates pressure and velocity within a fluid flow and can be used to explain how aircraft wings generate lift and how venturi tubes work. It involves the conservation of energy and mass within a fluid system.
liquid state and its properties
Definite Volume
Not Definite Shape
Molecules Are Much Closer Than Gases
Intermolecular Forces In Between Solids And Gases
properties of liquids
Evaporation
Process Of Changing A Liquid Into A Gas Phase
For example, liquid water conversion into vapor form
Cooling Process
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This document provides an overview of key units and concepts used in the International System of Units (SI) including:
- The seven base SI units of the meter, kilogram, second, kelvin, mole, ampere, and candela. Derived units are derived from base units.
- Prefixes used for very small or large units like kilo, milli, micro, and nano to express units concisely.
- Conversion of temperature units between kelvin, celsius and fahrenheit scales.
- Conversion of pressure units between pascals, atmospheres, bars, psi, torr and mmHg. Gauge pressure indicates difference from atmosphere.
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Liquids have properties like vapor pressure, boiling point, viscosity, and surface tension. Vapor pressure is the pressure exerted by a liquid's vapor when evaporation equals condensation. Boiling point is the temperature at which a liquid's vapor pressure equals atmospheric pressure. Surface tension is the force acting perpendicular to a liquid's surface. Viscosity is the frictional force between layers of liquid moving at different speeds past each other.
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Atmospheric pressure decreases with increasing altitude due to less air above. The barometric formula models how pressure and density change with altitude, dropping off exponentially. At sea level, air has a density of about 1.2 kg/m3 under standard temperature and pressure, but density decreases with altitude as pressure and temperature drop under the effects of gravity and the dry adiabatic lapse rate.
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hi viewers,
this is Ishita Soni of class VII-B.I study in GD Goenka Public School. This is a knowledge sharing presentation on convection. Please have a quick glance on it so that i have a good response and experience so that i come up with more attractive presentations later.
THNX
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Heat is a form of energy that can flow into or out of a system via various mechanisms. There are three main mechanisms of heat flow: conduction through direct contact of materials, convection through the mixing and movement of heated portions of a fluid, and radiation through electromagnetic waves. Common applications of heat transfer include evaporation, distillation, drying, crystallization, and sterilization. Heat transfer equipment like tubular heaters, floating head heaters, and heat exchangers facilitate heat exchange between fluids or between fluids and their environments.
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The document provides information about physics concepts related to pressure and temperature measurement. It discusses:
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- Operation of barometers, manometers and gas thermometers to measure pressure and temperature. Barometers use mercury columns, while manometers use liquid columns differentially to measure gas pressures. Gas thermometers use the direct relationship between gas pressure and temperature at constant volume.
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The document provides information about physics concepts related to pressure and temperature measurement. It discusses:
- Definitions of pressure, standard pressure units like pascals, and relationships between pressure, force, and area.
- How manometers and barometers can be used to measure gas pressure and atmospheric pressure.
- The relationship between temperature and gas pressure in a constant volume gas thermometer according to Boyle's law.
- Latent heat and heating curves related to phase changes of materials like water.
- Example problems for calculating pressure, heat transfer during phase changes, and using manometers to determine unknown pressures.
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This document provides an overview of key units and concepts used in the International System of Units (SI) including:
- The seven base SI units of the meter, kilogram, second, kelvin, mole, ampere, and candela. Derived units are derived from base units.
- Prefixes used for very small or large units like kilo, milli, micro, and nano to express units concisely.
- Conversion of temperature units between kelvin, celsius and fahrenheit scales.
- Conversion of pressure units between pascals, atmospheres, bars, psi, torr and mmHg. Gauge pressure indicates difference from atmosphere.
- Vapor pressure, which indicates how
The liquid state
Liquids have properties like vapor pressure, boiling point, viscosity, and surface tension. Vapor pressure is the pressure exerted by a liquid's vapor when evaporation equals condensation. Boiling point is the temperature at which a liquid's vapor pressure equals atmospheric pressure. Surface tension is the force acting perpendicular to a liquid's surface. Viscosity is the frictional force between layers of liquid moving at different speeds past each other.
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Atmospheric pressure decreases with increasing altitude due to less air above. The barometric formula models how pressure and density change with altitude, dropping off exponentially. At sea level, air has a density of about 1.2 kg/m3 under standard temperature and pressure, but density decreases with altitude as pressure and temperature drop under the effects of gravity and the dry adiabatic lapse rate.
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This document discusses psychrometric terms and relations. It defines dry air, moist air, saturated air, degree of saturation, humidity, absolute humidity, relative humidity, dry bulb temperature, wet bulb temperature, wet bulb depression, dew point temperature, dew point depression, and psychrometer. It describes Dalton's law of partial pressures and key psychrometric relations regarding specific humidity, degree of saturation, relative humidity, pressure of water vapor, and absolute humidity. An example problem is included to demonstrate calculating relative humidity, specific humidity, dew point temperature, enthalpy per kg of dry air, and volume of air mixture per kg of dry air given dry bulb temperature, wet bulb temperature, and barometric pressure.
Convection Lesson 3
Convection is a process of heat transfer where hotter less dense material rises and cooler, denser material sinks, causing circulation within fluids like gases and liquids. Convection occurs due to differences in density caused by variations in temperature, allowing heat to be transferred through the movement of the fluid. Examples of convection include heat transfer through gases and liquids, as well as phenomena like sea breezes that transfer heat and demonstrate the principles of convection.
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The document discusses several key concepts in hydrostatics:
1. It defines fluid pressure and provides an example calculation of pressure on a piston.
2. It explains Pascal's Law that pressure at a point in a fluid is the same in all directions.
3. It describes how pressure decreases with increasing height in a fluid under gravity.
4. It discusses pressure measurement using various devices like manometers and provides example calculations.
Convection of heat transfer
This document discusses heat transfer via convection. It defines the basic types of heat transfer and distinguishes between natural and forced convection. Natural convection occurs due to density differences in a fluid caused by temperature gradients, without an external source of motion. Forced convection uses an external source like a fan or pump to enhance fluid motion and heat transfer. The document also examines factors that affect the convective heat transfer coefficient and introduces the Nusselt and Prandtl numbers in analyzing dimensional relationships of natural convection.
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hi viewers,
this is Ishita Soni of class VII-B.I study in GD Goenka Public School. This is a knowledge sharing presentation on convection. Please have a quick glance on it so that i have a good response and experience so that i come up with more attractive presentations later.
THNX
gaseous state of matter
The document discusses the properties of gases and laws related to their behavior, including that gases diffuse and effuse due to their low density and wide spacing between molecules; Boyle's Law states that the volume of a gas is inversely proportional to its pressure when temperature is held constant; and as temperature decreases, the density of a gas increases because its molecules move more slowly and occupy less space.
Standard atmosphere
This document discusses the standard atmosphere and how atmospheric pressure varies with altitude. It provides information on how pressure decreases as altitude increases, dropping about 1.2 kPa for every 100 meters at low altitudes. The document also presents an equation called the barometric formula that relates atmospheric pressure, altitude, temperature, and other parameters in the troposphere. It includes a table with typical values for these parameters.
2014.10.28 pres cae_finale
This document discusses using computational fluid dynamics (CFD) to model thermal comfort in buildings. It presents a CFD study of transient heat transfer over a mixed radiative/convective system with time- and space-varying boundary conditions. The study analyzes natural convection, forced convection, and heat radiation phenomena. CFD is proposed as a method to model these phenomena and design new conditioning terminal products through simulation-based design. Integrating CFD with design allows simulation of physical fluid dynamics that are difficult to test experimentally.
Psychrometry and Air conditioning load estimation
This document discusses psychrometrics and air conditioning load estimation. It covers topics like:
- The composition of air and properties of moist air like humidity ratio, enthalpy, specific volume.
- Psychrometric chart which graphically represents thermodynamic properties of moist air.
- Basic psychrometric processes like sensible heating/cooling, humidification, dehumidification.
- Methods to achieve these processes like air washers, evaporative cooling, steam injection.
- Factors affecting human comfort and the use of comfort charts.
- Estimating cooling loads for air conditioning systems.
States of matter - Gaseous state
There are five states of matter: solid, liquid, gas, plasma, and Bose-Einstein condensate (BEC). Plasma is common among stars but not on Earth, while BEC only forms at extremely low temperatures near absolute zero when atoms lose kinetic energy and clump together. Gases are characterized by diffusion, the movement from high to low concentration, and effusion, movement through a small pore. Several gas laws describe gas behavior, including Boyle's law relating pressure and volume, Charles' law relating volume and temperature, Avogadro's law of equal volumes containing equal molecules, and Dalton's law of partial pressures. Real gases deviate from the ideal gas model due to intermolecular forces
Fluid flow, heat transfer & mass transfer
Fluid flow, Heat transfer & Mass transfer is a course that covers three topics:
1. Fluid flow can be laminar or turbulent, depending on factors like viscosity and velocity. Laminar flow occurs in layers while turbulent flow is disorganized.
2. Heat transfer occurs through conduction, convection, or radiation. Conduction involves energy transfer through direct contact. Convection involves energy transfer within a fluid through mixing. Radiation involves energy transfer through electromagnetic waves.
3. Understanding these topics is important for applications like manufacturing pharmaceuticals, administering drugs, and designing systems like cooling units.
Gaseous State SB
This document discusses the different states of matter and properties of gases. It begins by defining the four states of matter: gaseous, liquid, solid, and liquid crystalline. It then describes the general properties of gases, including their ability to expand infinitely and have low density. The document goes on to discuss ideal gases and the laws of Boyle, Charles, Gay-Lussac, and the combined gas law. It also covers the kinetic molecular theory and how the ideal gas law relates pressure, volume, temperature and moles of gas. Finally, it discusses how real gases differ from ideal gases and introduces the van der Waals equation to account for intermolecular forces.
Heat transfer
1. Heat transfer is the process of transfer of heat from a high temperature system to a low temperature system, and can occur through three modes: conduction, convection, and radiation.
2. There are different types of heat transfer based on whether convection occurs naturally via fluid currents or is forced through external means like pumps. Key applications of heat transfer include evaporation, distillation, drying, and sterilization.
3. The rate of heat transfer depends on factors like temperature difference, surface area, thickness, and the thermal conductivity or heat transfer coefficients of materials. Mechanisms like conduction follow Fourier's Law while convection involves heat transfer through fluid layers and stagnant films at surfaces.
Phase change heat transfer
basics of Phase Change Heat Transfer, including boiling, its types, regimes of boiling, condensation and types of condensation based on the mechanism.
Vapor pressure and boiling
The document discusses vapor pressure and boiling points. It explains that vapor pressure increases with temperature as more liquid molecules escape into the gas phase, creating pressure above the liquid. Boiling occurs when vapor pressure equals atmospheric pressure. Boiling point depends on the strength of molecular attractions, with stronger attractions yielding higher boiling points. Boiling points change with pressure, with lower pressure resulting in lower boiling points and higher pressure yielding higher boiling points.
Liquification of gases
There are three main methods for liquefying gases:
1. Applying sufficient pressure to gases below their critical temperature to cause liquefaction. For example, liquefying carbon dioxide which has a critical temperature of 304K.
2. Making gases do work against an external force, such as in a steam engine, causing them to lose energy and lower in temperature.
3. Forcing gases through a nozzle or porous plug, making them do work against their own internal forces and lose energy, potentially reaching liquefaction after multiple repetitions of expanding through restrictions.
Heat transfer and its application 1
Heat is a form of energy that can flow into or out of a system via various mechanisms. There are three main mechanisms of heat flow: conduction through direct contact of materials, convection through the mixing and movement of heated portions of a fluid, and radiation through electromagnetic waves. Common applications of heat transfer include evaporation, distillation, drying, crystallization, and sterilization. Heat transfer equipment like tubular heaters, floating head heaters, and heat exchangers facilitate heat exchange between fluids or between fluids and their environments.
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Presentation 1
- 1. CALCULATION OF AIR DENSITY PRESENTED BY: ANNAPOORNA.S CB.EN.P2RET16002 3/30/2017 1 ELECTRICAL AND ELECTRONICS DEPARTMENT AMRITA SCHOOL OF ENGINEERING, ETTIMADAI
- 2. 3/30/2017 2 DENSITY DEFINITION • The amount of matter in a given volume • “relative heaviness” • Intensive property • Density is constant for all sample size of a given substance Mass units: grams or kilograms Volume units: mL, L, or cm3 (solids)
- 4. 3/30/2017 4 DENSITY OF AIR • The density of air is the mass per unit volume of Earth's atmosphere. • Air density, like air pressure, decreases with increasing altitude. • It also changes with variation in temperature or humidity. • At sea level and at 15 °C air has a density of approximately 1.225 kg/m3 according to ISA (International Standard Atmosphere).
- 5. APPLICATIONS • Aeronautics science • Air conditioning industry • Meteorology • Power turbine powered airplanes • Gas turbine powered generators 3/30/2017 5
- 6. FACTORS AFFECTING AIR DENSITY • Altitude • Temperature • Pressure • Humidity • Composition 3/30/2017 6
- 7. 3/30/2017 7 AIR DENSITY CALCULATION METHOD 1: USING IDEAL GAS LAW • The density of dry air can be calculated using the ideal gas law expressed as a function of temperature and pressure.
- 8. GAS CONSTANT • The specific gas constant for dry air is 287.058 J/(kg·K) in SI units, and 53.35 (ft·lbf)/(lb·°R) in United States customary and Imperial units. This quantity may vary slightly depending on the molecular composition of air at a particular location. 3/30/2017 8 Rd = 287 J K-1 kg-1. The most common values of R are R = 0.082 057 L•atm•K⁻¹mol⁻¹ R = 8.3145 kPa•L•K⁻¹mol⁻¹ R = 8.3145 Pa•m³K⁻¹mol⁻¹ R = 8.3145 J•K⁻¹mol⁻¹
- 9. CONTD… 3/30/2017 9 Ru = Mgas R where Ru = universal gas constant Mgas = molecular weight of the ideal gas or mixture of gases
- 11. 3/30/2017 11 METHOD 2:PARTIAL PRESSURE METHOD • The addition of water vapour to air (making the air humid) reduces the density of the air. • This occurs because the molar mass of water (18 g/mol) is less than the molar mass of dry air (around 29 g/mol). • For any gas, at a given temperature and pressure, the number of molecules present is constant for a particular volume . So when water molecules are added to a given volume of air, the dry air molecules must decrease by the same number, to keep the pressure or temperature from increasing. Hence the mass per unit volume of the gas (its density) decreases.
- 12. CONTD… 3/30/2017 12 POINTS TO PONDER: •DALTONS LAW OF PARTIAL PRESSURE •PARTIAL PRESSURE=NUMBER OF MOLES OF A GAS/TOTAL NUMBER OF MOLES OF A MIXTURE •The vapor pressure of water may be calculated from the saturation vapour pressure and relative humidity. •Pv=Ø *Psat
- 13. 3/30/2017 13 DENSITY OF DRY AIR AT SEA LEVEL • Air density of dry air at sea level in international standard atmosphere conditions of pressure (1013.25 hPa or 101325Pa) and temperature (15oC). • Density = 101325 / (287.05 * (15 + 273.15)) = 1.225 kg/m3
- 14. EFFECT OF TEMPERATURE ON AIR DENSITY 3/30/2017 14 DENSITY IS INVERSELY PROPORTIONAL TO TEMPERATURE
- 15. AIR DENSITY AND ALTITUDE • Altitude is height above sea level. The density of air decreases with height. • The maximum air density is at the earth's surface; air density decreases with height away from the surface of the earth. There are two reasons: at higher altitudes, there is less air pushing down from above, and gravity is weaker farther from Earth's center. So at higher altitudes, air molecules can spread out more, and air density decreases. 3/30/2017 15
- 16. 3/30/2017 16 CALCULATIONS • ρ = ρ0-1.194*10^-4h • h=altitude • ρ0= 1.225 kg/m^3
- 17. 3/30/2017 17
- 18. 3/30/2017 18 DENSITY Vs HEIGHT
- 19. CONCLUSION • Air density depends upon temperature, pressure and altitude. • Air density decreases with increase in altitude. 3/30/2017 19
- 20. REFERENCES • Density of air-Wikipedia • Bright hub engineering • IEEE xplore 3/30/2017 20