Reference no: EM13318713
1. A moist airstream with a pressure of 100 kPa has an initial dry bulb of 30 °C and a wet bulb of 24 °C. Use the 100 kPa psychrometric chart provided to calculate the end dry/wet bulb to this original airstream when subjected to the following processes:
(a) Heating at constant moisture content, raising the specific enthalpy by 8 kJ/kg.
(b) Enthalpy increase of 8 kJ/kg, moisture content increases to 19 g/kg.
(c) Constant dry bulb cooling to a moisture content of 0.01 kg/kg.
(d) Constant dry bulb heating to a relative humidity of 90 %.
(e) Constant wet bulb (and sigma heat) process to a relative humidity of 30 %.
(f) Constant wet bulb process to saturation.
(g) Constant moisture content process to saturation.
2. The following two airstreams mix at the junctions of two roadways. The first airstream has a mass flow of 10 kg/s and a dry/wet bulb of 20/10 °C, the second airstream has a mass flow of 20 kg/s and a dry /wet bulb of 30/19 °C. The pressure is 100 kPa. Determine the dry/wet bulb temperatures of the mixed airstream.
If the mass flows were 20 kg/s for the first airstream and 10 kg/s for the second airstream, what would be the dry/wet bulb of the new mixed airstream?
3. For the following psychrometric combinations, calculate the dry/wet bulb temperature assuming a pressure of 100 kPa:
• 100 % relative humidity, 0.02 kg/kg dry air moisture content.
• Enthalpy of 70 kJ/kg, relative humidity of 20 %
• Sigma heat of 60 kJ/kg, moisture content of 0.0125 kg/kg dry air.
4. The radon daughter concentration leaving a mine section is 0.2 WL when the airflow is 20 m3/s. A temporary obstruction caused by stocked materials reduces the airflow to 5 m3/s. Determine the effect on the radon daughter concentration.
5. A mine opening is ventilated by an airflow of 15 m3/s. The exit concentration of radon daughters is 1.0 WL. If this is to be reduced to 0.33 WL, determine the required airflow.
|
Methods of methane drainage
: Describe the various methods of methane drainage available to drain gas for longwall mining operations and methane drainage of longwall operations what factors influence the spacing of drainage boreholes?
|
|
What force must the pump exert on the fluid
: A hydrulic jack in a mechanic's shop supports a car of mass M= 2.1 x 10^3 kg. What force must the pump exert on the fluid at the input to support the weight of the car
|
|
How much of the light passes through the first sphere
: To help you think about how illuminance varies with distance, suppose a small light source is placed at the center of two transparent spheres. how much of the light passes through the first sphere
|
|
Explain moles of naoh(aq) are formed in the solution
: NaCl(aq) + H2O(l) Cl2(g) + H2(g) + NaOH(aq) (b) How many moles of NaOH(aq) are formed in the solution in this process? _ moles of NaOH(aq) are formed.
|
|
Effect on the radon daughter concentration
: Determine the dry/wet bulb temperatures of the mixed airstream and calculate the dry/wet bulb temperature assuming a pressure of 100 kPa and determine the effect on the radon daughter concentration.
|
|
Determine the volume of the unknown material
: A sample of an unknown material weighs 300 N in air and 200 N when immersed in alcohol. The density of the alcohol is 70% the density of water. determine the volume of the unknown material
|
|
State a balanced equation of reaction
: Write a balanced equation of reaction. Carbon monoxide gas and oxygen gas combine to form carbon dioxide gas. Also, identify all the phases in the reaction.
|
|
Find minimum of the absolute value of the magnetic flux
: Determine the maximum and minimum of the absolute value of the magnetic flux through a large triangular wire loop that has three equal sides of 1.85 m
|
|
Determine the cumulative exposure in wlm
: Determine the cumulative exposure in WLM and determine the rate of emanation into the stope - working level of radon daughters at exit due to the initial radon
|