For an application for a Mechanical Engineering Internship Programme, a Mechanical Engineer must examine the operation of practical steam and gas turbines plants. The most efficient cycle is the Carnot cycle for given temperatures of source and sink. This applies to both gases and vapours.

However, the Rankine cycle is more suitable as a criterion for actual steam cycles than the Carnot cycle. In the application:

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a$)$ Justify why the Rankine cycle is preferred over the Carnot cycle in steam production plants around the world. Include diagrams to aid in your explanation.

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Evaluate the modifications made to the basic Rankine cycle to improve the overall efficiency of steam power plants. Include the reheat and regenerative cycles, along with economizers and pre$-$heaters. Discuss both the advantages and disadvantages of these modifications. Support your analysis with diagrams.

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c$)$ Explain, with the aid of diagrams, the principles of operation of steam turbine plants.

d$)$ Discuss, with the aid of diagrams, the principles of operation of gas turbine plants.

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After being successful in the application process, the Mechanical Engineer was presented with a problem on starting the Internship. It involved steam, which was supplied to a two$-$stage turbine at $40$ bar and

$350$C$.$ It expanded in the first turbine until it is just dry saturated, then it was re$-$heated to $350$C and expanded through the second$-$stage turbine. The condenser pressure was $0\mathrm{.}035$ bar. Calculate:

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e$)$ The work output

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f$)$ The heat supplied per kilogram of steam for the plant, assuming ideal processes and neglecting the feed$-$pump term

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g$)$ The specific steam consumption

h$)$ The cycle efficiency

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If the expansion processes in the turbine had isentropic efficiencies of $84\%$ and $78\%$ respectively, in the first and second stages, calculate:

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i$)$ The work output

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j$)$ The heat supplied per kilogram of team

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k$)$ The cycle efficiency

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l$)$ The specific steam consumption.