IN. J. Hear Mass Transfer.

Vol. 5, pp. 113-115.

TO ERNST

Pergamon Press 1962.

SCHMIDT

Printed in Great Britain.

ON HIS 70TH BIRTHDAY

special volume is dedicated to a scientist who started his work in the pioneer days of heattransfer research and who not only essentially influenced the early formulations of this science,
but who also contributed continuously to its development to the present time.
Ernst Heinrich Schmidt was born on 11 February, 1892 in the village of VSgelsen near Liineburg
in the northwestern part of Germany, an area inhabited by the Westphalian branch of the Germanpeople known for their strong sense of independence. E. Schmidt started his college years in 1909
at the Institute of Technology, Dresden, and continued at the Institute of Technology, Munich.
During the First World War, which interrupted his studies, he served as a lieutenant in the Signal
Corps of the German Army. After the end of hostilities, he continued his studies in ElectricalEngineering and received his diploma in 1919. In 1918 he became assistant in the Institute forApplied Physics of the University, Munich, a position which he held from 1918 to 1922, during
which time he received his doctor’s degree for a thesis on vibrations in machine foundations. During
the years 1922 to 1925, he was chief of a research institute for heat economy at Munich financed byindustry. This activity instigated him to invent among others his heat flux meter, an instrument
which is widely used for the measurement of heat losses in industrial devices. During this period
E. Schmidt also obtained his habilitation at the Institute of Technology in Munich with a thesis on
thermal radiation of solid materials.
In 1925 he was called to the Institute of Technology at Danzig to become Professor and Directorof the Engine Laboratory as successor to Rudolf Plank who had moved to Karlsruhe. He started hisactivity with a lecture on the performance of finned surfaces, published in the Journal of the German
Engineering Society (VDZ), and today still considered as one of the basic contributions to thissubject. The time from 1925 to 1937, in which he worked not only himself on many research projects
but also guided a considerable number of students in their thesis work, belongs to the most fruitfulperiods in his life. The Engine Laboratory soon achieved international recognition through hisstudies.
In 1936, the Institute of Technology at Dresden offered him’a Professorship in succession to thefamous thermodynamicist Richard Mollier; however, the Head of the National Socialist Party ofSaxony did not approve, and he moved in 1937 to Braunschweig, joining a newly founded Aeronautical Research Establishment (LFA) to head one of its institutes, with the task of organizing anddeveloping basic research in aircraft propulsion. E. Schmidt gathered around him a group of outstanding scientists, many of whom were his previous students, and soon had a research effort under way
which encompassed all fields of propulsion. He himself obviously felt that an understanding of combustion processes was the weak link in the development of aircraft engines and therefore devoted
much of his own time to a study of combustion. A device to which he gave his special attention was
the gas turbine capable of operation at high gas temperatures.
At the end of the Second World War, the Aeronautical Research Establishment was occupied
at first by American troops and afterwards by the British. E. Schmidt received an offer to continue
his research in the United States. He went instead, not completely on a voluntary basis, to England
where he worked for a short period. Returning to Braunschweig, he took up a position as Professorof Thermodynamics at the Institute of Technology. The following years were the years of reconstruction in Germany and E. Schmidt succeeded in establishing a new well-designed andequipped laboratory. Just when it was finished, he was offered a Professorship at the Institute ofTechnology in Munich as successor to Wilhelm Nusselt. He accepted and occupied the Chair for
Thermodynamics and the attached Institute until his retirement in 1960. The fact that he becameTHISA

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ERNST

R.

G.

ECKERI

Professor Emeritus in this year, however, meant for him characteristically
only that the releasefrom his representational
and administrative
duties should give him again more time for his scientificactivity which he now pursues with the same vigor as ever before.
The scientific areas to which E. Schmidt contributed
are so numerous that only the most significant ones can be discussed. Following up his investigationof radiative properties published in hishabilitation
thesis, he measured with instrumentsof his own design hemisphericaland directionalemissivities for a number of solid surfaces and liquids of engineering
importanceas well as theemissivities of water vapor up to 1000°C. As a true engineer, he always found novel applications
for the knowledge gained through his research. Thus he obtained a patent for the use of aluminium
foil for thermal insulation.
Such an insulation
equals in its heat conduction
properties the best
known insulating materials and surpasses them by its small heat capacity. Today, after expirationof the patent, it is in practically general use and found in each household.
A held in which our present-day knowledge is largely based on E. Schmidt’s work is heat transfer
by natural convection. After some early publications
on home heating equipment, he published hisclassical paper on natural convection at a vertical plate. His measurementsof the local heat flux.
of the velocity and temperaturefield, done partially with newly invented instruments,
gave a complete experimental
description of this heat transfer process and enabled E. Pohlhausen
to solve therelevant boundary layer equations.
Schmidt also introduced
a new schlieren method to the studyof this field and demonstrated
how quantitative
information
on heat transfer and boundary layer
thickness can be obtained from such photographs.
More recently his interest turned to a study of thestrong natural convection currents which arise in a fluid close to its critical state. Based on the knowledge gained in this way, he proposed a new cooling method for the rotor blades of gas turbines.
A number of experimental
turbines with this cooling method were built during the last war and an
industrial turbine of this type has now successfully completed its trial runs in an industrial plant inGermany.
In recognitionof his contributions
to this field, he was, at the suggestion of Ludwig
Prandtl, invited to present a summarizing paper on heat transfer at the Fourth International
Congress
for Applied Mechanics at Cambridge and again at one of the annual lectures held in commemoration of Ludwig Prandtl. An analytical study published in 1929 demonstrated
the similarities between
heat and mass transfer and pointed out the possibility
to utilize information
on heat transfer
for the calculationof mass transfer processes. This paper, publishedsimultaneouslywith andindependentlyof a paper on the same subject by W. Nusselt, created the basis for our treatmentof mass transfer processes. He also recognized
the possibilityof dropwise condensation
andmeasured the large heat transfer coefficients connectedwith it. A series of publications
weredevoted to the study of natural circulation in steam boilers.
His excellent experimental
skill and inventivenessis demonstrated
by precision measurements
ofvarious thermodynamic
properties
which he or his students performed.
These measurements
include the heat conductivityof water, carbon dioxide, and other fluids, the viscosity of water vapor.
and the state properties of CO, near and at its critical condition. For his measurements,
he designed
new instruments
which enabled him to exceed considerably
the accuracy of reported data.
During the period at Braunschweig,
he paid special attention to combustion
problems, guiding
his co-workers in various research projects in this area. Publications
on knocking and on early
reactions in combustion
engines, on photographic
studies revealing the details of combustion
processes in tubes are the outcome of this activity. This work is also reflected in the part “TheFoundationsof Chemical Thermodynamics”
which he added in 1950 to his book on Engineering
Thermodynamics.
The book itself, first published in 1936, has found such a widespread recognition
that it is today in its 8th edition. It has been translated into a number of foreign languages and is
the standard textbook at the German Institutes of Technology. He also prepared treatises on various
aspects of thermodynamics
and heat transfer for the engineering
handbook
Hiitte, for the classic
collection of physical properties generally known under the abbreviatedname Landolt-Bb’rnsteirz
in its new edition which was published after the last war, and in the VDI Heat Transfer Atlas. He also

TO ERNSTSCHMIDT

ON HIS 70TH

BIRTHDAY

115

took care of the recent editions of the VDI steam tables. Through a long number of years he served
the scientific community as editor of the magazine Forschung auf dem Gebiete des Ingenieurwesens,
which was founded by Max Jakob, and as chairman of the VDI Committee for Thermodynamic
Research.
In recognition of his scientific contributions, E. Schmidt received, among others, the Leibnitz
prize, the Grashof gold medal, and the Cross of Merit of the government of the German Federal
Republic. He was awarded honorary doctorates by the Institute of Technology at Aachen
and by the University of Glasgow, Scotland. He was a member of the pre-war German Academy for
Aeronautical Research and is still a member of the Bavarian Academy of Sciences. The recognition,
however, which is probably most valuable to him is the fact that a large number of his former
students and co-workers who have learned from his extraordinary experimental and analytical skill
continue his work in responsible positions all over the Western World, and that all join on hisbirthday in wishing him many more active and happy years.
ERNST R. G. ECKERT