FACULTY OF MECHANICAL AND MANUFACTURING ENGINEERINGTHERMODYNAMICS I(BDA20703 / BDA20202)

INDIVIDUAL ASSIGNMENT 1

Instruction: Answer all questions, submit within 1 week after the issuance date.

Q1 What are the difference between a thermodynamics open system and a closed system? *You need to sketch both systems, and differentiate them in terms of boundary, and energy that crossing the boundaries (as work and heat).

Q2 A manometer shown in Figure 1 is attached to a pipe to measure the air pressure inside it. The manometer is being constructed with an open arm is inclined 40° from the horizontal plane. The fluid inside the manometer is having density of 0.9 kg/L. If the vertical distance between the fluid levels in the two arms of the manometer is 10 cm, determine

i. the gage pressure of air inside the pipe;the length of the fluid column in the inclined arm above the fluid level in the vertical arm; and

ii. why does the manometer arm is inclined rather than vertically designed?

Figure 1

Q3 A double-U manometer with a pressure gauge is connected to a gasoline pipe as shown in Figure 2. If the reading of the pressure gage is 570 kPa, determine the gage pressure of the gasoline inside the pipe line.

Figure 2

Q4 i) What are the energy transfer mechanisms for:a) a closed system (fixed mass); andb) an open system.

ii) Derive the general energy balance equation for:a) a closed system; andb) an open system.

Q5 Complete the following table for H2O (water):

StateT, °C

P, kPa

h, kJ/kg

x Phase

1 200 0.72 140 18003 950 04 80 5005 800 3162.2

Show all the calculation methods to complete the table, and plot position of each state on a T-v and P-v diagram.

Q6 For the following process:

“Compressed liquid refrigerant (R-134a) at 0°C and 300kPa is being heated at constant pressure until its temperature reaches 20°C. The compression process then takes place isothermally until its specific volume reaches 0.0184 m3/kg”. Sketch the process change from initial to final state on a T-v diagram (complete with the saturation line), plot each state clearly and show their axis values on the diagram. Describe the phases of each state.