Author: admin
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What is relative humidity?
Relative humidity also measures water vapor in the air, but it is compared to the maximum amount of water vapor that can exist in the air at its current temperature. It is written as a percent. For example, warm air can hold more water vapor, or moisture, than cold air. So, with the same amount…
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What is absolute humidity?
Absolute humidity is the actual amount of water vapor in the air. The higher the amount of water vapor, the higher the absolute humidity.
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What is water vapor?
Water is a super special substance. It is basically everywhere on Earth – in our soils, our oceans, and our air. Water exists in three states – liquid, solid, and gas. Liquid water helps hydrate us during a hot day or after a long sports game. Solid water, or ice, is colder and gives us…
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What Is Humidity?
Imagine: You take a nice, long, hot shower. Stepping out, you feel it’s pretty muggy and warm in the bathroom, and the mirror is foggy. You wipe your hand across the mirror and suddenly, your hand is all wet. That’s because of the moisture in the bathroom! Water vapor in the bathroom allows us to…
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Thermodynamics
From the first law of thermodynamics for a closed reacting system we have���−���=��−�� where, ��� and ��� are the heat and work transferred from the system to the surroundings during the process, respectively, and �� and �� are the internal energy of the reactants and products, respectively. In the constant volume adiabatic flame temperature case, the volume of the system is held constant and hence…
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Common flame temperatures
Assuming initial atmospheric conditions (1 bar and 20 °C), the following table[1] lists the flame temperature for various fuels under constant pressure conditions. The temperatures mentioned here are for a stoichiometric fuel-oxidizer mixture (i.e. equivalence ratio φ = 1). Note that these are theoretical, not actual, flame temperatures produced by a flame that loses no heat. The closest will be the hottest part of a…
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Common flames
In daily life, the vast majority of flames one encounters are those caused by rapid oxidation of hydrocarbons in materials such as wood, wax, fat, plastics, propane, and gasoline. The constant-pressure adiabatic flame temperature of such substances in air is in a relatively narrow range around 1,950 °C (2,220 K; 3,540 °F). This is mostly because the heat of combustion of these compounds is roughly proportional to the amount of…
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Adiabatic flame temperature
In the study of combustion, the adiabatic flame temperature is the temperature reached by a flame under ideal conditions. It is an upper bound of the temperature that is reached in actual processes. There are a types of adiabatic flame temperature: constant volume and constant pressure, depending on how the process is completed. The constant volume adiabatic flame temperature is the temperature that results from…
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Heaters and Coolers
Heaters Operating temperatures can be classified into three ranges: low (< 120C), medium (120-250C), and high (>250C). low temperature-range heaters generally tend to use condensate or steam, medium temperature-range heater tend to steam, and high temperature-range heaters tend to use fired heaters or hot oil loops (<400C) Temperature and required heat load are important factors…
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Condensing Heat Transfer
Condensing heat transfer is important because many heat transfer applications will condense the steam used as the hot stream, and often gaseous products are needed in liquid form. There are two types of condenser: total condensers and partial condensers. Both total and partial condensers need to account for the accumulation of noncondensable vapor. This can…