Question

a. c. Question 1: State three thermodynamic properties of a good refrigerant. b. State three reasons that make the air-standard refrigeration cycle more suitable than vapor compression cycles for aircraft cooling applications. In a gas mixture, which component will have the higher partial pressure-the one with the higher mole number or the one with the larger molecular weight d. At standard conditions of 250C and 1 bar, are the enthalpies of formation of H2 and H (monoatomic hydrogen) different or identical? State three advantages of the two stroke engine over the four stroke engines f. A stream of atmospheric air of specific humidity wa passes through a water spray and comes out with wb. Under what conditions, if any, would wb< wa e.

Answer 1

1.
a) three thermodynamics properties of good refrigerant are as follows.
1} Boiling point - Low Boiling point is desirable for atmospheric of refrigerant.

2} freezing point - freezing point is important thermodynamic property of refrigerant. refrigerant should not freeze under required evaporator temperature.

3} Latent heat of refrigerant - when refrigerant evaporate same a high Latent heat is desirable.

b) size of vapour compression cycle is small as compared to air standard system.

Initial cost is high of vapour compression system. Costly refrigerant.

Refrigerant is environment hazardous.

c) In gas mixture, one with larger molecular weight have the higher partial pressure.

e) Design of two stroke engine is very simple and easier to fix it as compared to four stroke.

two stroke engine creates more torque and rpm than four stroke engine.

Two-stroke engines are lighter, and cost less to manufacture.