Search for tag: "efficiency"

13a Heat engines

Here I introduce the concept of the heat engine. I define the source and the sink. I then use the first and second laws of thermodynamics to derive the Carnot efficiency. I then point out that the…

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14c Brayton cycle with inefficiencies

Here I introduce two ineffinciencies into the ideal Brayton cycle I described in the previous lecture. Firstly, the effect of friction on the turbine and compressore. Then, I look at the effect of…

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14b Example of Brayton cycle

Here I go through an example of a Brayton cycle. I show that, using previous knowledge of devices, we can calculte the heat and work terms for the three devices and therefore work out the efficiency…

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12d Second law examples: Compressor and Nozzle

Here I work through two examples of the effect of isentropic efficiency on devices. I use the nozzle and the compressor as examples. I show that you need to produce a system and a T-S diagram. THen…

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14a The Brayton cycle

Here I introduce an example of a power cycle. The open cycle Air, Brayton cycle. I look at the three elements and describe what happens in each one. THe I go throught a description of a rea jet…

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13c The Carnot cycle

Here I introduce an example of the Carnot cycle (open using air). I show that it forms a rectangle on the T-S diagram. I then show that this is the maximum efficiency of a heat engine cycle as: 1)…

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13b Power cycles and diagrams

Here I show that the area under the PV and TS diagrams are the work produced in a cycle. I show (again that the efficiency is the ratio between work out and heat in, but here I do it graphcally.

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11c Efficiencies and the T-s diagram

Here I introduce the concept of efficiency. I show how these can be shown on a T-s diagram. THis gives the isentropic efficiency.

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11c Second law processes and the T-s diagram

Here I introduce the T-s diagram for ideal gasses. I show that an isentropic expansion is a vertical upward line on this and an isentropic compression is a vertical downward line. I then show that in…

From  Stephen Beck 0 likes 1,181 plays 0  

12e Throttle valves, enthalpy and entropy

We look at the throttle valve,, which is a constant enthalpy device. We see that it reduces pressure and increases the entropy of the flow. THen we compare the throttle to a turbine to get a better…

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