Humidification

Question 1

science behind the humification processes which refers mainly to the systematized knowledge of the properties of air and water

Answer 1

Psychrometry

Question 2

• Its broader meaning includes the principles which govern the properties and behavior of mixtures of the so called “fixed” gases with condensable vapors.

Answer 2

Psychrometry

Question 3

The mass of vapor carried by a unit mass of vapor-free gas

Answer 3

Saturation/Humidity

Question 4

Saturation Equation

Answer 4

S= (M_a/M_b) * p_a/(P-p_a)

Where,
* PA – the partial pressure of the vapor in the mixture
* P - the total pressure (usually atmospheric unless otherwise specified)
* MA, MB – the molecular weights of components A and B, respectively

Question 5

A gas in which the vapor is in equilibrium with the liquid at the gas temperature and pressure

Answer 5

Saturated Gas

Question 6

—– temp, —– capacity to hold vapor

Answer 6

higher, higher

Question 7

—– pressure, —- capacity for vapor

Answer 7

higher, lesser

in this condition, there would be higher tendency for vapor to condense

Question 8

at this point the partial pressure of that vapor in the gas mixture is equal to the saturation pressure of that vapor at a particular pressure and temperature.

Answer 8

Saturated Gas

Question 9

A gas in which the water vapor is in equilibrium with the liquid water at the gas temperature and pressure.

Answer 9

Saturated Air

Question 10

• Ratio of the partial pressure of the vapor to the vapor pressure of the liquid at the gas temperature and pressure.

Answer 10

Relative Saturation, RS

Question 11

Relative Saturation formula

Answer 11

%RS = (Pa/P*sat) x 100%

Question 12

Saturated Gas Formula

Answer 12

Psat*=pa

Question 13

Ratio of the actual saturation S (actual humidity, H) to the maximum saturation Smax (saturation humidity, HS) at the gas temperature and pressure.

Answer 13

Percentage Saturation

Question 14

%S =

Answer 14

%S=S/S_max ×100%
=(pa/(P-pa ))/((Psat)/(P-Psat ))×100%
=%RS (P-Psat)/(P-pa )

Question 15

• the temperature at which the vapor just starts to condense

Answer 15

Dew Point

Question 16

• at this point, the partial pressure of the vapor is the vapor pressure.

Answer 16

Dew point

Question 17

Dew Point Formula

Answer 17

ln⁡(P_sat^* )=A-B/(C+T)

Question 18

Dew pt for air-water system

Answer 18

ln⁡〖P_sat^* (mmHg)〗=18.3036-3816.44/(T(K)-46.13)

Question 19

• The total volume of a unit mass of vapor-free gas plus whatever vapor it may contain at 1 atm (or any specified pressure) and temperature.

Answer 19

Humid volume (vH)

Question 20

υ_H

Answer 20

υ_H=(RT/P) (1/M_B +S/M_A )

Question 21

B

Answer 21

gas

Question 22

A

Answer 22

vapor

Question 23

• The heat energy necessary to increase the temperature of a unit mass of gas plus whatever vapor it may contain by 1°C or 1°F.

Answer 23

Humid heat (Cs)

Question 24

Humid Heat SI Formula

Answer 24

C_s=1.005+1.88H kJ/(kg dry air ∙K) (SI)

Question 25

Humid heat AES Formula

Answer 25

C_s=0.24+0.45H BTU/(〖lb〗_m dry air ∙℉) (AES)

Question 26

Total Enthalpy

Answer 26

H_y=C_(P,B) (T-T_0 )+Sλ_0+C_(P,A) S(T-T_0 ) or H_y=C_s (T-T_0 )+Sλ_0

Question 27

Total Enthalpy SI Formula

Answer 27

H_y=(1.005+1.88H)(T-T_0 )+2501.4H kJ/(kg dry air∙K) (SI)

Question 28

* The temperature that would be attained if the gas were saturated in an adiabatic process.

Answer 28

Adiabatic Saturation Temperature (Ts)

Question 29

* The steady-state temperature attained by a wet-bulb thermometer under standardized conditions.

Answer 29

Wet-Bulb Temperature (Tw)

Question 30

* The actual gas (air) temperature as measured by a thermometer suitably shielded from radiation and moisture.

Answer 30

Dry-Bulb Temperature (T)

Question 31

* The maximum temperature a particular gas will obtained.

Answer 31

Adiabatic Saturation Temperature (Ts)

Question 32

* The steady-state nonequilibrium temperature reached when a small amount of water is contacted under adiabatic conditions by a continuous gas stream.

Answer 32

Wet Bulb Temperature

Question 33

* This means that for air-water system, the adiabatic saturation lines and the psychrometric lines are identical for a psychrometric chart.

Answer 33

Lewis Relation