3rd Class Thermodynamics exam help from Martin's Marine Engineering Page

Certification Assistance for Marine Engineers

Canadian Third Class ME 
Thermodynamics

In Canada, Transport Canada administers the Marine Engineering examination process; visit the Training Page for details on the process. The actual exam consist of nine (9) questions randomly drawn from a question bank of the various subject. Six (only) must be answered in a 3.5hrs time frame. The exam questions are similar to these, presented below, and are drawn heavily from similar question in the Reed's Marine Engineering series of books. 
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Disclaimer
Transport Canada has ask us to advise users of this webpage to keep in mind that these questions are not the exact questions found in their exams. Martin's Marine Engineering Page - www.dieselduck.net is not affiliated with Transport Canada and these questions have been gathered from various sources.

As I come across more questions, I will post them - if you have some, submit here.

Martin

 

1. 15 kg of steel ball bearings @ 100 C are immersed in 25 kg of water @ 20 C. Assuming no loss of heat to or from the container, calculate the final temperature of the water after equilibrium has been attained.
Specific heat of steel : 0.4857ki(kgK)
Specific heat of water : 4.187 kJ(kgK)

2. 
(i) State Charle's Law.
(ii) An air receiver carries a pressure of 3500 kPa absolute @ a temperature of 25 C. A fire occurs near the receiver which causes the temperature to rise to 80 C. Neglecting the increased volume of the receiver due to expansion, calculate the air pressure at this temperature.

3. A diesel engine is being assembled in a shop where the temperature is kept @ 20 C. At this temperature, the length of a steel valve push-rod is 460 mm. Calculate the clearance required if the engine is expected to reach an operating temperature of 96 C. 
Linear coefficient (steel) : (12)(10-6)/ 0C.

4. The following related values of the pressure p in kN/m2 and the volume V in cubic meter where measured from the compression curve of an internal combustion engine indicator diagram. Assuming that P and V are connected by the law PVn: C, find the value of n.
p 3450 2350 1725 680 270 130
V .0085 .0113 .0142 .0283 .0566 .0991

5. A continuous flow calorimeter was used to obtain the calorific value of a sample of fuel and the following data collected: 
Mass of fuel: 2.25kg 
Inlet water temp: ll C
Quantity of water: 360 L 
Outlet water temp: 60 C
Calorimeter efficiency: 85 %
Calculate the calorific value of the sample (kJ/kg).

6. The steel cables supporting the "Lion's Gate" suspension bridge are approximately 1200 metres long. If the temperature ranges from -9 to 26 C between winter and summer extremes, calculate the variation in the length of thg cables.
Linear coefficient (steel) : (12)(10-6)/OC.

7. 
(i) State Boyle's Law.
(ii) A receiver contains 0.25 m3 of air at a pressure of 1700 kPa and a temperature of 18 C. After a long period of time, the pressure is found to be the same as that of the atmosphere due to an extremely small leak. If the expansion is assumed to be isothermal, calculate the volume of air at the reduced pressure.

8. The following data were taken during a one-hour trial run on a single cylinder, single acting, four-stroke diesel engine with a cylinder diameter of 175 mm and a stroke of 225 mm, the speed being constant @ 1000 rpm
Indicated mep: 5.5 bar
Dia. of rope brake: 1066 mm
Load on brake: 400 N
Reading of balance: 27 N
Fuel consumed 5.7 kg
Calorific value 44.2 Mi/kg

Calculate the indicated power, brake power, specific fuel consumption per indicated kWh and per brake kWh, mechanical efficiency, indicated thermal and brake thermal efficiency.

9. In a single cylinder, four stroke, single acting gas engine, the cylinder dia. is 180 mm and the stroke is 350 mm. When running @ 250 rpm, the mean area of the indicator diagrams taken off the engine is 355 mm, length of diagram 75 mm, scale of the indicator spring 90 kN/m2 per mm, and the number of explosions was counted to be 114 per minute. Calculate the indicated power ?

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Disclaimer
Transport Canada has ask us to advise users of this webpage to keep in mind that these questions are not the exact questions found in their exams. Martin's Marine Engineering Page - www.dieselduck.net is not affiliated with Transport Canada and these questions have been gathered from various sources.