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1 AD THE THERMAL CONDUCTIVITY OF PURE WATER AND STANDARD SEA WATER AS A FUNCTION OF PRESSURE AND TEMPERATURE. PART III. STANDARD SEA WATER V. John Castelli, et al Naval Ship Research and Development Center Annapolis, Maryland November 1972 DISTRIBUTED BY: National Technical Information Service U. S. DEPARTMENT OF COMMERCE 5285 Port Royal Road, Springfield Va

2 II NAVAL SHIPRESEARCH AND DEVELOPMENT CENTER BetI, da. Md *THE TERMAL CONDUCTIVITY OF PURE WATER AM STANDARD ISEA WATER AS A FUNCTION OP.PRESSURE AND TEERATURE E4 V Part III - Standard 6ea Water 4-1 "0" 4j $41 'eqby w ~Qw V. John Castelli and 2, X,. Stanley I. 3 'k Approved for public release; distribution unlimited. - oe 01E1 4"4 4 w MATERIALS DEPARTMENT 4J k Annapolis 0 4RESEARCH AND DEYELOP;,,ENT REPORT Reproduced by [M D D C, 00 NATIONAL TECHNICAL INFORMATION SERVICE!, C SSpi,,ifbid U r. 0portnron of C~,immerce.44, VA 22151,B November 1972 taeport 3566 ov

3 The $aval 3u9 RemseascaIud Dfweowpmoe Costor is a V. N 3mavy enter for laboratory Ifm dirs"to at achievia" ls0v04d see and mittv*ielcles. J,- woo tamed 40 March 1967 by m*clog the David Taylor Model Dawn t Cotrd4ack.Maorylind waik the Marine aniln*erjnfi Loburatory at Aa~imppolit, Maiyland. Navau Whip Revearch and Dovelopment Center IBethesda. Md. 2W034 MAJOR NSRDC ORGANIZATIONAL COMPONENTS O wiandfr 0 * ORIGINATOR TECHNICAL D1RiCTO7% 1 SREPORT - OFFICER-IN.CHARGE OFFICER-IM-04ARGE CARDNROCK ANNAPOLIS u SYSTEMS DEVELOPMENT DEPARTMENT SHIP, DEHPART1ENRdTIC PERORMANCE DEPARTMENT SURFACE AVIATION EFFECTS AND OEPARTMENT 16.n xacturesnt AND MATHEMATICS -. lf2 -D -WA ENT 17 DEPARTMENT 1:,.,,, L.. D... 'S ACOUSTICS AUXILIARY SYSTEMS... PARTMENT 19 DEPARTMENT. AL.SAL CENTRAL SINSTRUMENTATION

4 Security Classification UNCLASSIFIED DOCUMENT CONTROL DATA - R & D (security classification of tille. body of abstract and indexing annotation must be ented when the ove...l report Is classiled) 1. ORIGINATING ACTIVITY (CoPporate author) 2a. REPORT SECU.RITY CLASSIFICATION Naval Ship Research & Development Center Annapolis Laboratory Unclassified 2b. GROUP Annapolis, Maryland REPORT TITLE i The Thermal Conductivity of Pure Water and Standard Sea Water as a Function of Pressure and Temperature 4. DESCRIPTIVE NOTES (Type of report and Inclusive date&) Research and Development 5. AUTHOR($S (Firet name, middle initial, loat name) V. J. Castelli and E. M. Stanley }. REPORT DATE 741. TOTAL NO. OF PAGES OF REPS November 1972_ 6 8&, CONTRACT OR GRANT NO. 9a. ORIGINATOR'S REPORT NUIMBER(S) b. PROJECT NO. Task Area SF C. Task b. OTHER REPORT NOMI (Any other numbers thatmay be a. sined this report) d. Work Unit t0' DISTRIOUTION STATEMENT Approved for public release; distribution unlimited. II. SUPPLEMENTARY NOTES IT. SPONSORING MILITARY ACTIVITY I NVSHIPS (ships 901K) 1". 6!4ACT Z Data are presented fbr the thermal conductivity of standard sea water over 0' to 3& C, at pressure to 1400 bars. An analysis of the results is given and comparison of the data with theoretical calculations for K at atmospheric pressure presented. Comparison of this data with that for pure water shows the thermal conductivity of sea water to be less of a function of pressure. (Authors) V.(PAGE 1) FORM SIN N'6v,/ UNCLSSSIFIED "curity se C'lasisl(fi ton

5 SCUrity ClsiiainUNCLASSIFIED 1.LINK A LINK S LINK KEY WOROS ROLE WT ROLE WT ROLE WT Thermal conductivity Sea Water Temperature Pressure Apparatus Thermal diffusivity 1K, N, IPON I DD 'A'?.e.1473 (BACK) (P AGE' 2) UNqCLASSIFIED security Ciaasuircation

6 DEPARTMENT OF THE NAVY. NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER -U BETHESDA,MD STANDARD SEA WATER AS A FUNCTION OF PRESSURE AND TEMPERATURE 3 iart III - Standard Sea Water fl aby U V. John Castelli and E. M. Stanley Approved for public release; distribution unlimited. 5 November 1972 IIReport 3566

7 4.3. I LI ABSTRACT Data are presented for the thermal conductivity of standard sea water over 0* U to 300 C, at pressure to 1400 bars. An analysis of the results is given and comparison of the data with theoretical calculations for K at atmospheric pressure presented. Comparison of this data with that for pure water shows the thermal conductivity of sea water to be less of a function of pressure. a2 N I iii

8 ADMINISTRATIVE INFOR.MATION[ This report is part of Task Area SF , Task 12874, Work Unit , as described in the 1 July 1972 Program Summary. The mention of proprietary products or devices by name in no way implies that they are endorsed by the U. S. Navy to the exclusion of other similar products or devices, nor may such mention be made in commercial advertising. iv

9 5 ITABLE OF CONTENTS Page ABSTRACT iii ADMINISTRATIVE INFORMATION iv O INTRODUCTION 1 I' I' EXPERIMENTAL INVESTIGATIONS 1 PRECISION, ACCURACY AND ERROR ANALYSIS 2 RESULTS 2 DISCUSSION 6 CONCLUSIONS 7 TECHNICAL REFERENCES 7 LIST OF FIGURES Figure 1 - Graph; Experimental Data for the Thermal 3 ~Conductivity of Standard Sea Water as a Function of Pressure for Various Temperatures Figure 2 - Graph; Thermal Conductivity of Standard 5 Sea Water as a Function of Pressure as Determined from Equation 1 at Various Temperatures INITIAL DISTRIBUTION -U Il I * V

10 U INTRODUCTION A continuing effort of oceanographic research at this [j activity is the determination of various chemical/physical properties of sea water as a function of pressure. Previous projects have included viscosity and refractive index measurements at pressure. The most recently completed project is the determination of thermal conductivity for sea water and pure water in the temperature range of 00 to 300 C* and the pressure Lrange of 0 to 1400 bars. This is the third and last in the series of reports and describes the experimental setup and results of the experimental determinations of the thermal conductivity for standard sea water. SU u EXPERIMENTAL INVESTIGATIONS Measurements of the thermal conductivity of standard sea water were conducted at temperatures of +1.82%, , , S and C and nominal pressures of 10, 200, , 1000, 1200, and 1400 bars. 1J LI [j]i The cleansing, filling, and setup procedures for the use of the special high-pressure experimental apparatus have been previously described.? The sea water used throughout this phase of the experiment was International Association of Physical Oceanography Standard Sea Water of Chlorinity L. Using the newly redefined relationship between chlorinity and salinity given by Wooster, et al,, as Salinity Chlorinity LI LI \IA yields a value of o/o0 salinity for the water used in this experiment. *Abbreviations used in this text are from the GPO Style Manual, 1967, unless otherwise noted. 'Superscripts refer to similarly numbered entries in the Technical References at the end of the text. 1! 1 N'

11 I 3 PRECISION, ACCURACY AND ERROR ANALYS', S I In these measurements, as previously, two distinct series were conducted with different thermocouple junctions. Each series consisted of at least three determinations of each data. point and many determinations of selected "reference" data points, primarily at 10 bars pressure. In almost all cases, the data resultant from any particular series agreed to within 0.3% of the mean value. The reasons for this variation, as well as a discussion of the accuracy and a complete error analysis have been previously described. 3 RESULTS The corrected results of our determinations for standard sea water are listed in table 1, and are shown graphically in figure 1. 1 ~ ~ A 1 -,nimr., comuctiv'it (10-.5 WA,,T,,/CM-G) OF' 4.994m s"',m SEA WATER AS A F CTIrN [I ~OF TM'PBMATURE AM~ PRESSURE Temperature, * C Pressure -I 1I. I. - I.. I S o o o n.o o '05 S , o I W , O j , [ l* ,c I - Iron-constantan Thermocuple Junction II - Chrolel-Constantm Thermocouple Junction 2

12 II 6 + IRON-CONSTANTAN THERMOCOUPLE JUNCTION O3'2* C 0 0 CHROMAEL-CONSTANTAN THERMOCOUPLE + JUNCTION 0 i * C * C L] " C 0i U 11 o 0 1is1. w U Figure 1 - Experimental Data for the Thermal Conductivity of Standard Sea Water as a Function ef Pressure for Various Teoperaturas g I' 3 N ll,,,, *... ' '"...."'"... :.,,. " :'2

13 The data reported can be represented as a function of temperature I. and pressure by the equation LI. K = x 10"3 + 3.o1-025 x 10"7 P x 10-5 T x l0-9 3 (1) where: K = thermal conductivity, watto/cm-deg P = pressure, bars I T = temperature, 0 C. Values generated with this equation are listed in table 2 and LA are depicted graphically in figure 2. The equation yields values which have a standard error of ±1.7 x 10-5 watts/cm-deg, or ±0.28%, from the experimental data. I TABLE 2 - VALLES OF TBE THERMAL CONDUCTIVITY OF STANDARD SEA WATER.. k AS DETERMINED FROM EQUATION (1) Pressure Temperature, C. B Ears Atmosphere oo

14 I' ~I1 I I I I " C S20 C U ~630 Llh LJ2 00 C UI, i ] 590- Ii S PRESSURE, BARS S Figure 2 - Thermal Conductivity of Standard Sea Water as a Function of Pressure as Determined from Equation 1 at Various Temperatures 15

15 SJDISCUSSION Investigation of the basic properties of sea water has been neglected for many years. However, with the recent upsurge of interest regarding maximum utilization of all our natural marine resources has emerged the realization that we lack much basic knowledge concerning the properties of sea water for engineering design. These experiments are an excellent case in point. While interest in the thermal conductivity of pure water has attracted 30-odd investigators over the last 50 years, we could not find one zesearcher who developed a similar interest in sea water. L Since there have been no direct measurements of K for sea water, educated guesses about its value were advanced as early as 1907 by Krummel.4 He assumed that thermal diffusivity (the thermal conductivity divided by the product of density and the specific heat) is approximately the same for both fresh water and sea water. Using this proposition, Barrett and Nettleton 6 computed K at C for sea water during their compilation for the International Critical Tables. The value they gave for 35 o/oo salinity is 5.58 x 10-5 watts/cm-deg. We obtain a value of 5.83 x 10-5 watts/cm-deg from equation (1). The discrepancy of 4.5%, we believe, can be traced to the invalid assumption previously noted. Currently accepted values are based upon the investigations of Riedel, 8 who compiled a table of molar conductivities for ions in aqueous solution at 200 C and 1 atmosphere. These contributions are utilized with the equation where: KSol + aici X0oI thermal conductivity of the solution ; K% 0 thermal conductivity of water LA 1] ai ci = molar thermal conductivity of the ion = molar concentration of the ion. "-_

16 Using values for the major ions in sea water indicates a decrease in the thermal conductivity on the order of about Sx i0-5 ýatts/cm-deg (for 35L salinity) over that for pure water at atmospheric pressure. Based upon our previously repurted values for pure water, we observe a decrease of from 4.5 to 10.0 x 10-5 watts/cm-deg from 00 to 3 0 * C. Li However, it should be mentioned that the difference between these calculated values and those measured experimentally is J hardly greater than 1% in the worst case. Ilistorical accounts of the effects of pressure on K for sea water are nonexist-nt, even on a theoretical basis. Our results indicate tiiat the thermal conductivity of sea water increpses cnl.y about 80% as fast as does the K for water for a Li similar pressure increase. This is a most unexpected result and might be related tj less rapid increase in density for sea water compared to pure water. L1 CCNCLJS IONS 0 The thermal conductivity of sea water is a direct function of pressure and temperature throughout the range studied. e Curiently accepted values for the thermal conductivity of sea water at atmospheric pressure may not be in L error by more than 1%. U I. The effects of pressure on the thermal condactivity of sea water are less than expected on Le basis of values for fresh water. TECHNICAL REFLRPMCES 1 - Stailey, E. M., and V. J. Castelli, "The T1,jrmal Conductivity of Pure Water and Standard Sea Water as a Function of Presbure and Temperature," NAVSHEPRANDCEN Annapolis Rept 3566, Part I (May 1972) S 2 -Wooster, W. S., et al, Deep Sea Research, Vol. 16, p. 321 (1969) U 3 - Castelli, V. J., and E. M. Stanley, "Thermal Conductivity of Pure Water and Standard Sea Water as a Function of Pressure and Temperature," NAVSHIPRANDCEN Annapolis Rept 3566, Part II (in preparation) 3 7

17 I 3 Lj. - Krummel, 0., Handbuch Der Oceanographie, Vol. 1, p. 280 (1907) 5 -. Barrett, T., and H. R. Nettleton, International Critical Tables, Vol. 5, p. 229 (1929) 36 Riedel, L., "Die Warmeleitfghigkeit von w*ssrigen L6sungen starker Electrolyte," Chem. Ing. Tech., Vol. 23, pp ii CO 0 Al u. A 1u H8