Eckert number

Physical key figure
Surname	Eckert number
Formula symbol	${\displaystyle {\mathit {Ec}}}$
dimension	dimensionless
definition	${\displaystyle {\mathit {Ec}}={\frac {v_{\infty }^{2}}{c_{\mathrm {p} }\cdot \Delta T}}}$
${\displaystyle v_{\infty }}$ Flow velocity ${\displaystyle c_{\mathrm {p} }}$ specific heat capacity ${\displaystyle \Delta T}$ Temperature difference
Named after	Ernst Eckert
scope of application	Dissipation at interfaces

The Eckert number is a dimensionless number that was named after the engineer and natural scientist Ernst Eckert (1904–2004). It is used in the field of heat transfer, for example to determine the dissipation and convection of heat at interfaces. ${\displaystyle {\mathit {Ec}}}$

The Eckert number is defined for compressible fluids . It can be written as the ratio of the kinetic energy of the fluid to the enthalpy difference between a wall or a body and the fluid around which it flows

${\displaystyle {\mathit {Ec}}={\frac {v_{\infty }^{2}}{c_{\mathrm {p} }\cdot \Delta T}}}$

The numerator is proportional to the kinetic energy of the undisturbed fluid, i.e. proportional to the square of the flow velocity of the fluid at a great distance from the wall. ${\displaystyle v_{\infty }}$

The entalpy difference in the denominator is calculated from the temperature difference between the wall and the fluid at a great distance from the wall, where is the isobaric specific heat capacity of the fluid. ${\displaystyle \Delta T=T_{\mathrm {w} }-T_{\infty }}$ ${\displaystyle c_{\mathrm {p} }}$

literature

• Heinz Herwig: Fluid Mechanics AZ: A systematic classification of terms and concepts in fluid mechanics. Vieweg, Wiesbaden 2004, ISBN 3-528-03974-4 , p. 87.

Individual evidence

1. ^ Josef Kunes: Dimensionless Physical Quantities in Science and Engineering . Elsevier, 2012, ISBN 0-12-391458-2 , pp. 191 f . ( limited preview in Google Book search).