log-mean temperature difference

log-mean temperature difference

[′läg ¦mēn ′tem·prə·chər ‚dif·rəns]
(thermodynamics)
The log-mean temperature difference TLM = (T2-T1)/ln T2/ T1, where T2 and T1 are the absolute (K or °R) temperatures of the two extremes being averaged; used in heat transfer calculations in which one fluid is cooled or heated by a second held separate by pipes or process vessel walls.