Available online
Description
The significance of the second law to engineering is examined.
The significance of the second law to engineering is examined.
| Module code and title: | T231, Introduction to engineering mechanics |
|---|---|
| Item code: | T231; 11 |
| First transmission date: | 13-07-1975 |
| Published: | 1975 |
| Rights Statement: | |
| Restrictions on use: | |
| Duration: | 00:24:09 |
| + Show more... | |
| Producer: | Andrew Crilly |
| Contributors: | John Cannell; Richard Pefley |
| Publisher: | BBC Open University |
| Keyword(s): | Carnot Heat Engine; Condenser; Developmental engineers; Engineering; Heat pump; Planck statement; Reversible; Steam generating plant; Theoretical maximum efficiency |
| Footage description: | John Cannell briefly introduces the programme. Dick Pefley explains why the second law is important for engineering applications. He then goes through several statements of the second law as made by Carnot (1824), Clausius (1850), Kelvin (1851) and Planck (1903). Pefley takes one of the statements (Planck's) and applies it to a steam power plant. He uses a model of the plant and diagrams. Pefley discusses the concept of irreversible processes using a small pendulum to demonstrate his points. Still shot of Foucault pendulum which approaches reversibility by having the damping effect minimised. Pefley performs the glycerine experiment on the face of it, seems to demonstrate a reversible process. Pefley explains why this is not so. Pefley draws a flow diagram of an ideal, reversible Carnot engine on a board. He uses this to demonstrate the concept of thermal efficiency. Pefley calculates the maximum efficiency which represents the target figure for development engineers. He then applies these concepts to a steam power plant and discusses ways in which the plant can maximise efficiency. A model of a steam power plant is used as an aid. Pefley, with the flow diagram of an ideal Carnot engine, explains what will happen if the machine is run in reverse. He introduces the concept of coefficient of performance. The result of this reversal of the Carnot engine is shown to be a refrigerator. Several working models of heat engines are demonstrated. Pefley also shows slides of an RB 211 engine and one of Hero's engine (an ancient, primitive steam engine). John Cannell sums up. Shots of Nuffield College, Oxford and the heat pump which heats the buildings. Cannell explains how it works. |
| Master spool number: | 6HT/71804 |
| Production number: | 00525_5111 |
| Videofinder number: | 2227 |
| Available to public: | no |
