Mechanical Engineering Answers

1 kg of steam initially dry saturated at 1.1 MPa expands in a cylinder as per pv^1.13 = Constant. The pressure at the end of expansion is 0.1 MPa. Determine

(a) The final volume

(b) Final dryness fraction

(c) Workdone and

(d) Heat transferred

Steam issues from the nozzle of a single-impulse turbine at

800 m/sec on to blades moving at 300 m/sec. The blade tip angles

at inlet and outlet are 36º each. The steam is to enter the blades

without shock and the flow over the blades is frictionless.

Determine—

(a) the angle at which the nozzles are inclined to the motion of the

blades;

(b) diagram efficiency.

In a reaction turbine, the mean blade ring diameter is 1 m and the

turbine runs at a speed of 50 RPS. The blades are designed for 50% 

reaction with exit angles 30º and inlet angles 50º. The turbine is

supplied with steam at the rate of 160 kg/sec and the stage

efficiency is 85%. Determine—

(a) power output of the stage;

(b) percentage increase in relative velocity.

Design a standalone (off grid) PV system for the households in the village so that the following electrical appliances can be utilized: • 1 x 18 W fluorescent lamp running for 4 hours per day • 1 x 60 W fan run for 2 hours per day • 1 x 75 W refrigerator that runs 24 hours per day with compressor that runs 12 hours and off 12 hours The system will be powered by 12 VDC, 110 W PV module.

In a game, a card is taken at random from a full pack of 52 playing cards. It is then replaced, and a second card is taken. What is the probability that both cards are diamonds? O 0.225 O 0.625 O 0.0625 O 0.5 O 0.125

Design a standalone (off grid) PV system for the households in the village so that the following electrical appliances can be utilized: • 1 x 18 W fluorescent lamp running for 4 hours per day • 1 x 60 W fan run for 2 hours per day • 1 x 75 W refrigerator that runs 24 hours per day with compressor that runs 12 hours and off 12 hours The system will be powered by 12 VDC, 110 W PV module. Description 1 Project aim 2 Project theoretical background 3 Project problem statement 4 Specifications (material to be used for the project) 5 Method used for communication 6 Challenges experienced 7 Number meetings attended 8 Meetings attendance list attached 9 Calculation of power consumption demand 10 Calculation of size of the PV panel/s (number of PV panels required)

A refrigerator operates on the reversed Carnot cycle and uses water as the working

fluid. At the beginning of the isothermal expansion, the steam has an absolute

pressure of 1kPa and a quality of 7%; at the end of the isothermal expansion, the

steam is dry and saturated. At the end of heat rejection process the water is saturated

liquid. Firstly: Sketch the T‐s and P‐v diagrams for the cycle, and secondly: for one kg

of water, calculate: a) The steam pressure at beginning of the heat rejection process,

b) the net work per cycle, c) the COP of the cycle in two conditions: 1‐refrigeration

and 2‐heat pump

Please refer to the table below for the aspects that need to be covered on the project.

Item Description 1 Project aim,2 Project theoretical background,3 Project problem statement4 Specifications (material to be used for the project),5 Method used for communication6 Challenges experienced,7 Number of meetings attended,8 Meetings attendance list attached,9 Calculation of power consumption demand10 Calculation of size of the PV panel/s (number of PV panels required)11 Calculation of the inverter size,12 Calculation of the battery size (number of batteries required),13 Calculation of solar charge controller size14 Project layout (block diagram),15 Recommendations,16 Conclusion17 If the same system was to be designed in Thailand: Determine the number of PV panels required to perform the same task Is the number of the PV panels used in South Africa the same as the number of the PV panels used in Thailand? If YES/NO why?

Question:

Continue the two sequences of numbers below and find an equation to each of the sequences: n 1 2 3 4 5 6 7 Equation an 2 5 9 14 20 27 bn 1 3 12 60 360 2520

Please tell the complete solution of this question.Briefly