THERMO-SYSTEM ANALYSIS

3) Explain production of gasohol, not exceeding one page

Iron has an fcc structure at temperatures higher than 913 degree centigrade, and bcc structure below this temperature. At 1148 oC, iron can dissolve maximum of 2.08% of carbon to form steel. However, at temperature lower than 723 oC, iron can only dissolve maximum 0.025% carbon. The atomic radius is 0.129 nm in both structures (don't consider thermal expansion). One of the largest void is located at (0, ½ , 0) for fcc.

What is the largest void size in the fcc structure of iron?

Iron has an fcc structure at temperatures higher than 913 degree centigrade, and bcc structure below this temperature. At 1148 oC, iron can dissolve maximum of 2.08% of carbon to form steel. However, at temperature lower than 723 oC, iron can only dissolve maximum 0.025% carbon. The atomic radius is 0.129 nm in both structures (don't consider thermal expansion). One of the largest void is located at (0, ½ , 0) for fcc.

What is the largest void size in the fcc structure of iron?

A thermocouple junction of 1.0-mm in diameter is inserted in a large chamber to measure the temperature of hot gas flowing through the chamber. The hot gas has a velocity of 2 m/s and temperature (Tg) at 800 K. The chamber surface (Ts) is maintained at 500 K.

(a) If the thermocouple is at room temperature, Ti when it is inserted in the chamber, calculate the time required for the temperature difference, (Tg–T) to reach 2% of the initial temperature difference Tg-Ti . Neglect radiation and conduction through the leads. Properties of the thermocouple junction are approximated as k = 100W/mK, c = 385 J/kgK and  = 8920 kg/m3 , while those of the hot gases may be assumed to have the properties of air at atmospheric pressure.

(b) If the thermocouple junction has an emissivity of 0.5, what is the steady state temperature of the thermocouple junction?

(c) The emissivity of the thermocouple junction can be controlled through application of a thin coating. How would changes in the emissivity affect the temperature measurement error? Compute the steady state junction temperature for emissivities in the range 0.1  ɛ  1. Results are to be presented in graphical and / or tabular forms and should be accompanied by substantial discussion supported by heat transfer fundamentals.

(d) Suggest ways to eliminate the temperature measurement error

A refrigerator with R-410a as the working fluid has a minimum temperature of −10°C and a maximum pressure of 1 MPa. Assuming an ideal refrigeration cycle, find the specific heat transfer FROM the cold space, the specific heat transfer TO the hot space, and the coefficient of performance. Will this refrigeration cycle work in an ordinary kitchen?

Explain the concept of the TTT diagram, e.g why is there a “nose”?

How are cooling rates controlled to produce coarse and fine pearlite/bainite?

Applications of low, medium, and high-carbon steels, cast irons, stainless steels

Q1. Describe mechanical properties of stress-strain behavior of a polymer and a plastic (contrast with stress-strain curves of ceramics and metals)

Q2. Describe variation of elastic/relaxation modulus with temperature.

Q3. Describe viscoelasticity and examples of a rubber/elastomer.

•A hydraulic motor has a 22-in3 volumetric displacement. If it has a pressure rating of 1200 psi and it receives oil from a 15 gpm theoretical flow rate pump, find the motor a) speed, b) theoretical torque and c) theoretical horsepower.

Describe how both the X and R or s chart would look if they were under normal statistical control.

A large bank established X-Bar and R charts for the time required to process applications for its charge cards. A sample of five applications is taken each day. The first four weeks (20 days) of data give:
X bar bar = 16 min s bar = 3 min R bar = 7 min
Based on the values given, calculate the centerline and control limits for the X bar and R charts.

7. When studying a process control chart tracking one variable, what is meant by the statement, "The process is in a state of statistical control"

How do you calculate the factor of safety for a worm in a worm gear drive? I am looking for the mathematical equations to calculate this. Linking outside resources would be much appreciated.

A closed, rigid, 0.40 m³ tank is filled with 15 kg of water. The initial pressure is p₁ = 20 bar. The water is cooled until the pressure is p₂= 4 bar.

Determine the initial quality, x₁, and the heat transfer, in kJ.