Introduction                       1780 - 1888                       1888 - 1971                     1971 - today         ...
Introduction                        1780 - 1888                    1888 - 1971   1971 - today       Conclusions        A f...
Introduction   1780 - 1888   1888 - 1971   1971 - today   Conclusions                1780 - 1888                The early ...
Introduction            1780 - 1888             1888 - 1971           1971 - today           Conclusions1780 J. Priestley ...
Introduction                        1780 - 1888                       1888 - 1971            1971 - today   Conclusions178...
Introduction                        1780 - 1888                        1888 - 1971                 1971 - today   Conclusi...
Introduction                       1780 - 1888     1888 - 1971   1971 - today      Conclusions1848 Sir William Robert Grov...
Introduction                        1780 - 1888     1888 - 1971   1971 - today      Conclusions1861 Gustav Magnus         ...
Introduction                        1780 - 1888                         1888 - 1971   1971 - today   Conclusions1863 John ...
Introduction                        1780 - 1888         1888 - 1971   1971 - today   Conclusions 1860 James Clerk Maxwell ...
Introduction                       1780 - 1888                      1888 - 1971     1971 - today   Conclusions 1872 Josef ...
Introduction                     1780 - 1888                         1888 - 1971     1971 - today           Conclusions 18...
Introduction                 1780 - 1888      1888 - 1971   1971 - today   Conclusions          The early days…1780       ...
Introduction   1780 - 1888   1888 - 1971   1971 - today   Conclusions                 1888 - 1971                 The evol...
Introduction                      1780 - 1888      1888 - 1971   1971 - today          Conclusions 1917 Sophus Weber      ...
Introduction                        1780 - 1888                1888 - 1971       1971 - today         Conclusions 1931 Ber...
Introduction                        1780 - 1888                       1888 - 1971        1971 - today   Conclusions 1938 A...
Introduction                       1780 - 1888                      1888 - 1971       1971 - today     Conclusions 1949 E....
Introduction                       1780 - 1888                      1888 - 1971    1971 - today          Conclusions 1949 ...
Introduction                        1780 - 1888          1888 - 1971           1971 - today           Conclusions 1952 D.A...
Introduction                     1780 - 1888                     1888 - 1971                   1971 - today   Conclusions ...
Introduction                      1780 - 1888                      1888 - 1971         1971 - today           Conclusions ...
Introduction                      1780 - 1888              1888 - 1971           1971 - today          Conclusions 1960 W....
Introduction                         1780 - 1888      1888 - 1971    1971 - today        Conclusions 1961 A.G. Turnbull (M...
Introduction                       1780 - 1888                         1888 - 1971   1971 - today     Conclusions 1963 J.K...
Introduction                      1780 - 1888                      1888 - 1971                    1971 - today            ...
Introduction                       1780 - 1888                1888 - 1971   1971 - today    Conclusions 1968 Harland L. Bu...
Introduction                        1780 - 1888                       1888 - 1971                  1971 - today   Conclusi...
Introduction                       1780 - 1888                       1888 - 1971    1971 - today   Conclusions 1971 E. McL...
Introduction                       1780 - 1888                       1888 - 1971    1971 - today        Conclusions 1971 E...
Introduction                     1780 - 1888                     1888 - 1971               1971 - today   Conclusions 1971...
Introduction                      1780 - 1888                      1888 - 1971   1971 - today   Conclusions 1971 J.W. Haar...
Introduction                 1780 - 1888       1888 - 1971            1971 - today                Conclusions            T...
Introduction   1780 - 1888   1888 - 1971   1971 - today   Conclusions                 1971 - today                 Todays ...
Introduction                        1780 - 1888                    1888 - 1971   1971 - today   Conclusions 1971          ...
Introduction                              1780 - 1888                             1888 - 1971                1971 - today ...
Introduction                              1780 - 1888                             1888 - 1971                             ...
Introduction                             1780 - 1888                            1888 - 1971                            197...
Introduction                               1780 - 1888                            1888 - 1971   1971 - today   Conclusions...
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THW - Transient Hot-Wire - A

  1. 1. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions A few words… Time used to be measured by the change of the moon… Now it is measured by the 2 ns between two sms! Instruments and techniques have changed.. have been developed, evolved or disappeared… new ones appear… faster, better… maybe more accurate, or not! and computers have become so much faster… In this section, we will walk through history to see the evolution and development of the THW technique… Not a thorough list of dates, numbers and equations but through designs and drawings of instruments. From Gases to Liquids, to Melts and Solids, and it is Still Going Strong! The section will include a typical selection of instruments in order to demonstrate its evolution and will certainly not include all investigators. M.J. Assael, K.E. Antoniadis, W.A. Wakeham, Int. J. Thermophys. 31:1051-1072 (2010).1/43 M.J. Assael, K.E. Antoniadis, Proc. 30th Int. Therm. Conduct. Conf. & 18th Int. Therm. Expansion Symp. 28 Aug. - 3 Sept. Pittsburg (2009).
  2. 2. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions A few more words… fluid Ideally, the thermal conductivity of the fluid is determined by observing the rate at which the temperature of a very thin metallic wire increases q (W/m) with time after a step change in voltage has been applied to it, thus creating in the fluid a line source of essentially constant heat flux per unit length. Approximate analysis (Healy 1976) wire q ln( 4kt ) of radius α q ΔTid = ΔΤ 4πλ α2C ρCp? 4πλ ΔTid = ΔΤw + Σ δTi t However today, It is much better, and much more accurate, to solve ΔΤ the full heat transfer equations for the wire and the fluid by FEM. whole curve ρCp & λ No approximations! t2/43 J.J. Healy, J.J. de Groot, and J. Kestin, Physica C, 82:392 (1976).
  3. 3. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1780 - 1888 The early days3/43
  4. 4. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions1780 J. Priestley GLNMS Joseph Priestley was probably the first, to carry out experiments to measure the gas power to conduct heat (i.e. the specific heat, which was unknown at that time…). In 1780, Joseph Priestley became a minister in Birmingham. He continued his scientific researches and also his theological ones. He expressed his views quite forcibly, and, in 1785, his History of the Corruptions of Christianity was publicly burned. In 1791, Priestley was driven out of Birmingham by a mob who destroyed his home. He had expressed support for the French Revolution, and so, on the second anniversary of the storming of the Bastille, the mob burned down his laboratory, which was at his home. He moved to USA.4/43
  5. 5. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions1786 Count Rumford (Sir Benjamin Thomson) GLNMS Count Rumford continued similar experiments examining "the conductive power of artificial airs or gases" and while doing so he stumbled on a completely new mode of heat transfer, convection. In 1799 Count Rumford concluded that "a gas was unable to conduct heat"!!! "Heat is incapable of passing through a mass of air, and that it is to this circumstance that its non-conducting power is principally owing" and because of his reputation, this conclusion was not challenged for many years. B. Thomson, Trans. Roy. Soc. London, 76:273-304 (1786).5/43 B. Thomson, "Essays, Political Economical, and Philosophical”, 1 st Am. Ed. vol 2:457 (1799). A.C. Burr, Isis, 21:169-186 (1934).
  6. 6. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions1804 Sir John Leslie GLNMS Sir John Leslie in "An Experimental Inquiry into the Nature and Propagation of Heat" (1804), wrote about Count Rumford: "A late ingenious experimenter, who by the perspicuity and useful tendency of his writings, is deservedly a favorite of the public, he advanced the paradoxical conclusion that fluids are non-conductors of heat ….. If the proposition, however, be taken in its strict sense, it is more palpably erroneous. Were fluids absolutely incapable of conducting heat, how could they ever become heated?... How could water, for instance, be heated by the content of warm air? But the question really deserves no serious discussion“.6/43 J. Leslie, "An Experimental Inquiry into the Nature and Propagation of Heat", Ist Ed, p.552 (1804).
  7. 7. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions1848 Sir William Robert Grove GLNMS In a communication illustrated by an experiment, he showed, that a platinum wire, rendered incandescent by a voltaic current, was cooled far below the point of incandescence when immersed in an atmosphere of hydrogen gas. "This was found not to be due to specific heat, nor to the conducting powers of the gases. Convection did not explain the fact; and considerable difficulty was found, upon examination, to exist, if it was attempted to refer it to the greater mobility of the particles of hydrogen gas, the tightest known, than of either oxygen, nitrogen, or carbonic acid. It was found that this peculiar property also belonged, but to a less extent, to all the compounds of hydrogen and carbon". NOTE : First experiments with heated wires...7/43 W.R. Grove, Phil. Mag. Series 3, 27:442-446 (1845). W.R. Grove, J. Franklin Institute, 46:358 (1848).
  8. 8. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions1861 Gustav Magnus GLNMS Gustav Magnus reported in Poggendorfs Annalen, immediately being translated into English and appearing in full in the Philosophical Magazine. "A platinum wire is less strongly heated by a galvanic current when surrounded by hydrogen than when it is in atmospheric air or any other gas. It cannot be doubted that hydrogen conducts heat, and that in a higher degree than all other gases". NOTE first experiments with heated wires…. G. Magnus, Phil. Mag. Series 4, 22:85-106 (1861).8/43 G. Magnus, J. Franklin Institute, 72:130-132 (1861).
  9. 9. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions1863 John Tyndall GLNMS John Tyndall in his book "Heat considered as a Mode of Motion" writes: "The subject of gaseous conduction has been recently taken by Prof. Magnus of Berlin, who considers that his experiments prove that hydrogen gas conducts heat like a metal…. Beautiful and ingenious as these experiments are (Magnus & Grove), I do not think they conclusively establish the conductivity of hydrogen…. Theories are indispensable, but they sometimes act like drugs upon the mind. Men grow fond of them as they do of dram-drinking…" Hot-wire employed by Tyndall9/43 J. Tyndall, "Heat considered as a Mode of Motion", 1 st Ed. p.239 (1863)
  10. 10. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1860 James Clerk Maxwell GLNMS James Clerk Maxwell publishes his groundbreaking paper on the dynamic theory of gases and he calculates a theoretical value of the thermal conductivity of a gas and showed its dependence on temperature and pressure. 1862 Rudolf Julius Emanuel Clausius backs up Maxwell, showing that thermal conductivity increased with temperature and was independent of pressure when the gas was ideal. J. C. Maxwell, Phil. Mag. Series 4, 19:19-32 (1860). J. C. Maxwell, Phil. Mag. Series 4, 20:21-37 (1860).10/43 R.J.E. Clausius, Phil. Mag. Series 4, 23:417-435 (1862). R.J.E. Clausius, Phil. Mag. Series 4, 23:512-534 (1862).
  11. 11. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1872 Josef Stefan GLNMS Josef Stefan with his experimental expertise (E=AT 4 law) set out to defy Maxwells words (Boltzmann was his student). He measured thermal conductivity of air with diathermometer (23.4 mW/mK - todays value is 26.3 mW/mK). The diathermometers principle was based on the energy balance equation -kA T dr = dQ = mC dT s Δx Rearranged to be expressed as a measure of pressures, as Τ λA ΔΡ Το = exp(- mC Δx t) = ΔP s o J. Stefan, Mathematische-Naturwissenschaftliche Classe Abteilung 2, 65:45-69 (1872).11/43 J. Crepeau, Exper. Thermal & Fluid Sci., 31:795-803 (2007).
  12. 12. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1888 August Schleiermacher GLNMS August Schleiermacher following the work of Josef Stefan and his predecessors set out to measure the thermal conductivity of gases by using a Pt hot wire (probably first real application of Hot Wire) Pt wire diameter 0.4 mm length 32 cm. Glass diameter 2.4 cm. Leads are soldered at A and B. Temperature outside registered by a wound resistance thermometer. Inside by measuring the resistance of wire. Equilibrium reached in minutes. Measured up to 1000 oC. When equilibrium is reached, measure I, V through wire and T1 and T2 Q λ=Α A = ln(d2/d1)/(2πl) or by measuring known gas. (T1-T2)12/43 A. Schleiermacher, Annalen der Physik und Chemie, 270:623-646 (1888). 3/13
  13. 13. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions The early days…1780 G First experiments in conduction (J. Priestley)1786 G "Gases do not conduct" (Count Rumford)1804 G Can not be so.. (J. Leslie)1848-61 G First experiments with heated wires (W.R. Grove & G. Magnus)1863 G Still doubts about conduction (J. Tyndall)1860-62 G Thermal conductivity theory (J.C. Maxwell & R.J.E. Clausius)1872 G Thermal conductivity measurement (J. Stefan)1888 G First hot wire - horizontal 4C (A. Schleiermacher)13/43
  14. 14. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1888 - 1971 The evolution of the Transient Hot-Wire14/43
  15. 15. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1917 Sophus Weber GLNMS The sources of errors involved in the determination of the thermal conductivity of gases by Schleiermacher’s method are subjected to a critical analysis, and a modified form of apparatus is described in which the errors due to convection are greatly reduced. Apparatus is placed vertically. With this improved form of apparatus, measurements of the thermal conductivity of a number of gases have been made. Pt wire The following values are recorded : 54.5 cm length, @ 0 oC mW/m/K 0.40 mm diameter. hydrogen. 174 168.4 internet neon, 45.5 49.2 (25 oC) Glass helium, 144 155.3 (25 oC) diameter 2.3 cm. argon, 16.1 16.6 Ref.val. nitrogen, 23.7 24.9 Ref.val. oxygen, 24.1 25.5 Ref.val. methane, 30.1 32.7 Ref.val. CO2 16.4 16.3 Ref.val. N2O 14.7 14.6 internet15/43 S. Weber, Annalen der Physik, 21:325-356 (1917). S. Weber, Annalen der Physik, 54:437-462 (1917).
  16. 16. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1931 Bertil Stâlhane & Sven Pyk GLNMS First transient hot wire. Employed to measure thermal conductivity of solids and powders (& liquids). They investigated the relationship between time and temperature rise, for a fine straight wire subjected to a step change in the heat input to the wire. They found that a short interval after the initiation of the step change, the following empirical relation holds: 2 A, B were found using fluids of ΔΤ = Aq ln( ro + B) λ t known thermal conductivity. On the diagram above, the wire is placed in the middle of powder. The upper and lower solids are kept at constant temperature. Temperatures are recorded by thermocouples. The diagram on the right shows another sensor for powders with a thermometer in the middle.16/43 B. Stâlhane and S. Pyk, Teknisk Tidskrift, 61:389-398 (1931).
  17. 17. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1938 A. Eucken & H. Eglert GLNMS They designed an absolute THW for low temperatures. The 0.1mm Pt wire is in the middle of the glass tube. - two wires serve as potential leads, and - two wires as supports. Temperature obtained from the wires resistance. Thermal conductivities measured were: - Benzene (0 to -78.5 oC), - Glycerin (0 to -78.5 oC), - Carbon dioxide (-103.9 oC), - Ammonia (-103.9 oC).17/43 A. Eucken and H. Englert, Zeitschrift fur die gesamte Kalte-Industrie, 45:109-118 (1938).
  18. 18. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1949 E.F.M. van der Held & F.G. van Drunen (Rijksuniversiteit Utrecht) GLNMS A Proved the empirical expression of Stâlhane & Pyk for the THW, by solving the Fourier equation q q ΔΤ = [-Εi (- 4αt )] ΔΤ = [ln 4αt - 0.5772… ] 4πλ r2 4πλ ro2 This can further be simplified by taking the difference in temperatures at two times as ΔΤ q t ΔΤ1 - ΔΤ2 = ln 2 λ 4πλ t1 ln t This way absolute measurements can be carried out. E.F.M. van der Held and F.G. van Drunen, Physica, 15:865-881 (1949).18/43 E.F.M. van der Held, J. Hardebol, and J. Kalshoven, Physica, 19:208-216 (1953).
  19. 19. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1949 E.F.M. van der Held & F.G. van Drunen (Rijksuniversiteit Utrecht) GLNMS B In order to develop a method for all liquids they used - a 0.3 mm diameter Mn wire and - a 0.1 mm diameter Copper/Constantan thermocouple both placed in a narrow capillary with both ends fused into the wall of a glass vessel. Liquid is placed between the capillary and the glass vessel. The glass vessel is placed in a Dewar flask for a steady temperature. They preferred to use thermocouple to record temperatures instead of recording the resistance of the wire, as the later would involve high temperature rises and complicated recorders and bridges. They made many corrections for the wire thickness and the presence of the glass and employed times in the region of 20-50 s. Measured the thermal conductivity of many fluids (hydrocarbons, alcohols, acids..) with a quoted uncertainty of ±2%. E.F.M. van der Held and F.G. van Drunen, Physica, 15:865-881 (1949).19/43 E.F.M. van der Held, J. Hardebol, and J. Kalshoven, Physica, 19:208-216 (1953).
  20. 20. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1952 D.A. de Vries (Landbouwhogeschool Holland) GLNMS De Vries employed a small modification of the original solution q q ΔΤ = [ln 4αt - 0.5772… ] ΔΤ = [d + ln(t + to ] 4πλ r2 4πλ Heating wire 0.1 mm diameter enameled constantan folded and placed inside the glass capillary of 0.4 mm outside diameter. Outside the capillary there is a fine monel gauze forming a socket of 1.4 mm diameter. The thermocouple wires are of enameled copper and constantan 0.1mm. The thermocouple wires and the glass capillary are introduced into the gauge cylinder, and the empty space is filled with paraffin wax. The whole sensor has a length of 10 cm. Resistance is measured with a sensitive D.C. Wheatstone bridge. Times of 3 min were employed. Daily trends in moisture content of soil reflected on the measurement of the thermal conductivity.20/43 D.A. de Vries, Soil Science, 73:83-89 (1952).
  21. 21. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1955 D.G. Gillam, L. Romben, H.-E. Nissen, O.Lamm (Stockholm) GLNMS They employed the ideas of Stâlhane & Pyk, and Eucken & Englert to produce a simpler apparatus of lower uncertainty, 0.3% for liquids and solids (of low melting point - melted solid, like liquid was poured into the glass and solidified there). They presented advances in the THW theory, and discussed zero time determination and specific heat capacity correction. Temperature obtained from the wires resistance. Pt Wire of 0.1 mm diameter and 10 cm length. Potential leads also welded Pt wires. Optimized Kelvin bridge to record accurately the resistance change. Times recorded between 1 - 60 s.21/43 D.G. Gillam, L. Romben, H.-E. Nissen, and O. Lamm, Acta Chemica Scandinavica, 9:641-656 (1955).
  22. 22. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1960 P. Grassman, W. Straumann (ETH Zurich) GLNMS They employed a relative THW, i.e. two THW one with a know thermal conductivity fluid, and the other with the unknown, both placed in the arms of a Wheatstone type bridge. Heating lasted a few seconds, and the quoted uncertainty was ±1%. Pt Wire of 70 μm diameter and 15 cm length. They registered resistance change from very low times (interesting diagram) but only employed top part to obtain the thermal conductivity.22/43 P. Grassman, and W. Straumann, Int. J. Heat Mass Transfer, 1:50-54 (1960).
  23. 23. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1960 W.E. Haupin (New Kensington) GLNMS He determined the thermal conductivity by placing into the specimen a line heat source consisting of a butt welded thermocouple heated by alternating current. At the same time, a filter network was used to eliminate the ac heating specimen current allowing the thermocouple emf to be measured. The thermocouple served both as a heat source and a thermometer. Materials measured were high-fired, superduty, firebricks and furnace insulation blocks.23/43 W.E. Haupin, Am. Ceram. Soc. Bull., 39:139-141 (1960).
  24. 24. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1961 A.G. Turnbull (Melbourne) GLNMS He employed a THW to measure thermal conductivity of molten salts both in liquid and solid state near their melting point (to confirm his theory on molten salts). Many salts like NaNO3, KNO3, NaCl, AgNO3, KHSO4, NH4HSO4, KCNS, ZnCl2, NaOH.24/43 A.G. Turnbull, Aust. J. Appl. Sci., 12:325-329 (1961).
  25. 25. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1963 J.K. Horrocks, E. McLaughlin (Imperial College, London) GLNMS Four-terminal THW, for the measurement of the thermal conductivity of liquids with an absolute uncertainty 0.25%. Full analysis of corrections a) finite wire diameter, b) boundary medium, c) finite wire length, d) study of convection and radiation. 1 cm diameter Glass cell. 60 μm Pt wire of 15 cm length, annealed for an hour. Pt potential leads 1 cm from ends. Pt spring at top (inside Pt strips) prevents wire sagging. Measurements performed within 30s. Temperature rise was calculated from the wires resistance change.25/43 J.K. Horrocks and E. McLaughlin, Proc. Roy. Soc. , A273:259-274 (1963).
  26. 26. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1964 A. von Mittenbuhler GLNMS The method employs a heating wire of one metal with a thermocouple welded to the heating wire in the form of a cross. An ac or dc power suplly can be employed, and the temperature rise generated by a known heating power is used to determine the thermal conductivity. The technique formed the basis for a German and a European standard in use today. A. von Mittenbuhler, Ber. Dtsch. Keram. Ges. 41:,15 (1964). Deutsches Institut für Normung. 1976. Testing of Ceramic Materials: Determination of Thermal Conductivity up to 1600oC by the Hot-Wire Method. Thermal Conductivity up to 2 W/m/K. DIN 51046.26/43 European Committee for Standardization. 1998. Methods of Testing Dense Shaped Refractory Products. Part 14: Determination of Thermal Conductivity by the Hot-Wire (Cross-Array) Method. EN 993-15.
  27. 27. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1968 Harland L. Burge, Lawrence Baylor Robinson (California Univ.) GLNMS Four-terminal THW, for the measurement of the thermal conductivity of gases. The line source consists of a 0.7 mm diameter, 20.6 cm length wire (alloy "evenohm"). Around it is tightly wrapped a 0.02 mm nickel temperature sensing coil. A 3-element copper-constantan thermocouple records gas temperature. Resistance change is recorded by a camera attached to a Tetronik oscilloscope connected to a dc resistance bridge. Times were limited to 0.27 s and temperature rise never exceed 10 oC. Thermal conductivity of He, Ne, Ar and their mixtures was measured.27/43 H.L. Burge, and L.B Robinson, J. Appl. Phys., 39:51-54 (1968).
  28. 28. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1971 K. Hayashi, M. Fukui, I. Uei (Kyoto Tech. Univ.) GLNMS Four-terminal THW, for solids up to 1200 OC. Wire: 0.3 mm diameter (constantan, alumel, Pt-Rh-13%) combined with thermocouple (chromel-constantan, chromel-alumel, Pt-Pt Rh13%). Measured thermal conductivity of fire clay brick, high alumina brick, chromite-magnesia brick. etc28/43 K. Hayashi, M. Fukui, and I. Uei, Mem. Fac. Ind. Arts, Kyoto Tech. Univ. Sci. Tech., 81-103 (1971).
  29. 29. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1971 E. McLaughlin, J.F.T. Pittman (Imperial College, London) GLNMS A Four-terminal THW, for liquids, 100-450 K and up to 10 MPa. Discussion on the ideal solution and following approximations: a) temperature dependent fluid properties, b) finite wire diameter, c) finite conductivity wire, d) wall effects, e) interfacial thermal resistance, f) time-dependent heat-source power, g) end effects, h) initial fluid temperature distribution.29/43 E. McLaughlin, and J.F.T. Pittman, Phil. Trans. R. Soc. Lond., A 270:579-602 (1971). E. McLaughlin, and J.F.T. Pittman, Phil. Trans. R. Soc. Lond., A 270:557-578 (1971).
  30. 30. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1971 E. McLaughlin, J.F.T. Pittman (Imperial College, London) GLNMS B Four-terminal THW, for liquids, 100-450 K and up to 10 MPa. Cell: 1 cm diameter SS. Wire: 25 μm diameter 15 cm length Pt. 1 cm from ends Pt potential leads. Small weight at the bottom ensures verticality. Wire annealed for 15 min. Elaborate temperature enclosure (heating and liquid nitrogen) with stability of 1mK/h. Measurement time 1 - 20 s. Instead of photographing galvanometer spots or using chart recorders, a digital voltmeter is employed to record the change in voltage because of the change in resistance. Temperature change is calculated from the wires resistance.30/43 E. McLaughlin, and J.F.T. Pittman, Phil. Trans. R. Soc. Lond., A 270:579-602 (1971). E. McLaughlin, and J.F.T. Pittman, Phil. Trans. R. Soc. Lond., A 270:557-578 (1971).
  31. 31. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1971 P.S. Davis, F. Theeuwes, R.J. Bearman, R.P. Gordon (Kansas Univ.) GLNMS Four-terminal THW, for electrically conducting liquids and salts. Wire: 6.2 μm diameter Pt wire of 1.3 cm length. 0.3 cm from ends Pt potential leads (T-shaped junction). Measurement time 1 - 10 s. Instead of photographing galvanometer spots or using chart recorders, a digital voltmeter (HP 2402A, 40 measurements/s) is employed to record the change in voltage because of the change in resistance, coupled to a precision frequency generator. Temperature change is calculated from the wires resistance. For electrically conducting fluids they used a thin metal film evaporated on a quartz rod. The quartz substrate rod was 1.25 mm long and had a diameter of 0.025 mm. The length of the sensing platinum film was 0.51 mm. The film is in contact with both ends with gold plated portions of the quartz rod. The resistance of the sensor was about 6 Ohm. This was employed as a relative instrument.31/43 P.S. Davis, F. Theewesm R.J. Bearman, and R.P. Gordon, J. Chem. Phys., 55:4776-4783 (1971).
  32. 32. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1971 J.W. Haarman (Delft) GLNMS His equipment used an automatic Wheatstone bridge to measure the resistance difference of two wires. The two wires were identical except for their length. Hence, end effects were subtracted. The bridge was also equipped with an electronic potential comparator. The bridge was capable of measuring the time required for the resistance of the hot wire to reach six predetermined values, with the aid of high-speed electronic switches and counters. This new bridge made possible a ten-fold reduction in the duration of each experimental run, eliminated completely the effects arising from convection and reduced greatly other time-dependent errors. J.W. Haarman, Physica, 52:605-619 (1971).32/43 J.W. Haarman, Ph.D thesis, Technische Hogeschool Delft, Netherlands (1969).
  33. 33. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions The early days… & The evolution of the Transient Hot Wire1780 G First experiments in 1952 STHW, 3 min, T=f (t/c) conduction (D.A. de Vries) (J. Priestley) 1955 LS THW, 1-60 s, T=f (R)1786 G "Gases do not conduct" (D.G. Gillam, L. Romben, H.-E. Nissen, O.Lamm ) (Count Rumford) 1960 GL 2 THW in Wheatstone bridge, 1-20 s1804 G Can not be so.. (P. Grassman & W. Sraumann) (J. Leslie) 1960 S THW1848-61 G First experiments with (W.E. Haupin) heated wires 1961 MS THW (W.R. Grove & G. Magnus) (A.G. Turnbull)1863 G Still doubts about 1963 L THW, analysis of errors, 30 s, T=f (R) conduction (J. Tyndall) (J.K. Horrocks & E. McLaughlin)1860-62 G Thermal conductivity 1964 STHW + t/c cross (basis for D & EU standards) theory (A. von Muttelbuhler) (J.C. Maxwell & R.J.E. Clausius) 1968 G THW, 30 s, T=f (t/c)1872 G Thermal conductivity (H.L. Burge & L.B. Robinson) measurement (J. Stefan) 1971 STHW, up to 1200C, T=f (t/c) (K. Hayashi, M. Fukui, I. Uei)1885 G First hot wire - horizontal 4C 1971 L THW, T=f (R), 20 s, Digital (A. Schleiermacher) voltmeter (E. McLaughlin & J.F.T. Pittman)1917 G Vertical hot wire (S. Weber) 1971 LSmall THW, 10 s, digital voltmeter (P.S. Davis,F. Theewes,R.J. Bearman,R.P. Gordon)1931 LS First transient hot wire, & theory33/43 (B. Stâlhane & S. Pyk) 1971 L2 wires, new, much faster electronic bridge (J.W. Haarman)1938 GL Absolute THW, T=f (R) (A. Eucken & H. Eglert)
  34. 34. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1971 - today Todays Transient Hot-Wires34/43
  35. 35. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1971 today The pioneering work of Haarman (use of 2 wires, faster electronic bridge, experimental time of seconds) was the start of a new series of THW instruments developed after 1971, most of them based theoretically in a paper by Healy in 1976. Since the majority of these new groups cooperated through research projects, very similar instruments appeared. Hence, they will be presented all together. Most of the THW groups nowdays originated from, or were connected to, - J. Kestin (Brown Univ., USA), or - W.A. Wakeham (Imperial College & Southampton Univ., UK). Such groups are: - C.A. Nieto de Castro & J.M.N.A. Fareleira (Portugal), - M.J. Assael (Aristotle Univ., Greece), - R. Perkins (NIST, U.S.A.), - A. Nagashima & Y. Nagasaka (Keio Univ., Japan). and more recently - J. Wu (Jiaotong Univ., China), - E. Vogel (Rostock Univ., Germany). In parallel, some more groups produced also excellent work, as - S.E. Gustaffson (Chalmers Univ., Sweden), - U. Hammerschmidt (PTB, Germany).35/43 J.J. Healy, J.J. de Groot, and J. Kestin, Physica C, 82:392 (1976).
  36. 36. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1971 today Development of THW Instruments for fluids GLNMS (anodized) Au (a) (b) (c) (d) (e) (a) J.J. de Groot, J. Kestin, and H. Sookiazian, Physica, 75:454-482 (1974). C.A. Nieto de Castro, J.C.G. Calado, W.A. Wakeham, and M. Dix, J. Phys. E: Sci. Instrum., 9:1073-1080 (1976). (b) J. Kestin, R. Paul, A.A. Clifford, and W.A. Wakeham, Physica, 100A:349-369 (1980). M.J. Assael, M. Dix, A. Lucas, and W.A. Wakeham, J. Chem.Soc.,Faraday Trans. I, 77:439-464 (1981). E.N. Haran, and W.A. Wakeham, J. Phys. E: Sci. Instrum.,15:839-842 (1982). (c) J. Menashe, and W.A. Wakeham, Ber. Bunsenges. Phys. Chem., 85:340 (1981). Y. Nagasaka, and A. Nagashima, J. Phys. E: Sci. Instrum., 14:1435-1440 (1981). W.A. Wakeham, and M.Zalaf, Physica, 139:105 (1986). E. Charitidou, M. Dix, C.A. Nieto de Castro, and W.A. Wakeham, Int. J. Thermophys., 8:511-519 (1987).36/43 (d) S.H. Jawad, M.J. Dix, and W.A. Wakeham, Int. J. Thermophys., 20:45-54 (1999). (e) M.J. Assael, C-F. Chen, I. Metaxa, and W.A. Wakeham, Int. J. Thermophys. 25:971-985 (2004) .
  37. 37. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1971 today Development of THW Instruments for melts & solids GLNMS (h) (g) (f) (i) (f) M.J. Assael, K.D. Antoniadis, K.E. Kakosimos, and I.N. Metaxa, Int. J. Thermophys., 29:445-456 (2008). (g) M.V. Peralta-Martinez, M.J. Assael, M. Dix, L. Karagiannidis, and W.A. Wakeham, Int. J. Thermophys., 27:353-375 (2006).37/43 (h) R. Model, R. Stosch, and U. Hammerschmidt, Int. J. Thermophys., 28:1447-1460 (2007). (i) S.E. Gustafsson, Rev. Sci. Instrum., 62:797-804 (1991).
  38. 38. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1971 today Development of THW automatic bridges GLNMS Electronic bridges were developed tremendously following advances in electronics and computers. An excellent series of bridges was developed in Imperial College by M. Dix, and these are shown here as example. (a) (b) (c) (a) J.J. de Groot, J. Kestin, and H. Sookiazian, Physica, 75:454-482 (1974). C.A. Nieto de Castro, J.C.G. Calado, W.A.Wakeham, and M. Dix, J. Phys. E: Sci. Instrum., 9:1073-1080 (1976). J. Kestin, R. Paul, A.A. Clifford, and W.A. Wakeham, Physica, 100A:349-369 (1980). M.J. Assael, M. Dix, A. Lucas, and W.A. Wakeham, J. Chem. Soc.,Faraday Trans. I, 77:439-464 (1981). (b) G.C. Maitland, M. Mustafa, M. Ross, R.D. Trengove, W.A. Wakeham, and M. Zalaf, Int. J.Thermophys., 7:245-258 (1986).38/43 M.J. Assael, E. Charitidou, G.P. Georgiades, and W.A. Wakeham, Ber.Bunsenges.Phys. Chem., 92:627-632 (1988). (c) M.J. Assael, C-F. Chen, I. Metaxa, and W.A. Wakeham, Int. J. Thermophys., 25:971-985 (2004).
  39. 39. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions 1971 today Measurement of the temperature rise GLNMS As an example, measurement of the thermal conductivity of BK7.39/43 M.J. Assael, K.D. Antoniadis, and J. Wu, Int. J. Thermophys., 29:1257-1266 (2008).

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