Page 332 - Mechanical Engineer's Data Handbook

320 MECHANICAL ENGINEER’S DATA HANDBOOK

interchange factor When two bodies are involved in jig boring Boring carried out on a ‘jig borer’ on which
the interchange of heat radiation, the radiation de- the positions of holes can be positioned to a high
pends upon the emissivities of both bodies. Inter- degree of accuracy.
change factor is a function of the emissivities which journal The portion of a rotating shaft which is
allows for this. supported in a bearing.
intercooler A cooler, usually using water, interposed journal bearing A bearing which supports a journal.
between air compressor stages.
internal combustion engine (I.C. engine) An engine in
which combustion takes place within a chamber, e.g. a Kaplan turbine A propeller water turbine with ad-
cylinder, and the products of combustion form the justable runner blades which are altered to suit the
working fluid, e.g. petrol engine, diesel engine, gas load.
engine. key A piece of material inserted between usually a
internal energy The difference between the heat en- shaft and a hub to prevent relative rotation and fitting
ergy supplied to a system and the work taken out. The into a ‘keyway’.
energy is in the form of heat as measured by the K factor A factor giving the proportion of, or number
temperature of the substance or its change of state. of, velocity head@) lost in a pipe or in pipe fittings.
inverse square law The intensity of a field of radiation kinematic viscosity The coefficient of viscosity
(light, heat, radio waves) is inversely proportional to divided by the fluid density.
the square of the distance from the source. kinetic energy The energy of a body arising from its
investment casting Casting of metal in a mould velocity. For a mass m at velocity v the kinetic energy is
produced by coating an expendable pattern made of $mv2.
wax, plastic, etc., which is removed by heating. Also
‘lost wax process’.
involute gear teeth Gear-wheel teeth the flank profile labyrinth gland A gland used on steam turbines, gas
of which consists of an involute curve. The commonest turbines, etc., with radial fins on a shaft or surrounding
form of gear teeth. casing, with small radial or axial clearance to limit
isenthalpic process A process taking place at con- fluid leakage.
stant enthalpy, e.g. a ‘throttling’ process. lagging Thermal insulation on the surface of a pipe,
isentropic efficiency Defined as the actual work from tank, etc.
the expansion of a gas, vapour, etc., divided by the laminar flow (viscous flow) Fluid flow in which
work done in an isentropic expansion. adjacent layers do not mix. It occurs at relatively low
isentropic expansion The expansion of a fluid at velocity and high viscosity.
constant entropy. lapping The finishing of spindles, bores, etc., to fine
isentropic process A thermodynamic process taking limits using a ‘lap’ of lead, brass, etc., in conjunction
place at constant entropy. with an abrasive.
isobaric process A thermodynamic process taking latent heat The heat required to change the ‘state’ of
place at constant pressure. a substance without temperature change, e.g. solid to
isothermal process A constant-temperature process. liquid, liquid to gas. The latent heat per unit mass is the
Izod test A pendulum type of single blow impact test ‘specific latent heat’.
using notched test pieces. lathe A versatile machine tool for producing cylin-
drical work by turning, facing, boring, screw cutting,
etc., using (usually) a single-point tool.
jet A fluid stream issuing from an orifice, nozzle, etc. lead The axial advance of a helix in one revolution,
jet engine An engine incorporating rotary compres- e.g. in screw thread or worm.
sor and turbine which produces a high-velocity jet for lift The component of force on a body in a fluid
the propulsion of aircraft. stream which is at right angles to the direction of flow.
jet proputsion The propulsion of vehicles, e.g. boat, The force which supports the weight of an aircraft.
aircraft, by means of a fluid jet. lift coefficient A non-dimensional quantity relating
jig A device to hold a workpiece and guide a tool in lift to the velocity and density of the fluid and the size of
cutting operations. the body.