1、Wind Tunnel Testing of External Reaffirmed 200 1 Floating-Roof Storage Tanks API PUBLICATION 2558 FIRST EDITION, JUNE 1993 American Petroleum Institute Helping You Get The Job Done Right? API PUBLX2558 93 O732290 0533878 OT5 SPECIAL NOTES 1. API PUBLICATIONS NECESSARILY ADDRESS PROBLEMS OF A GENERAL
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7、PI PUBLICATIONS AND MATERIALS IS PUBLISHED ANNUALLY AND UPDATED QUARTERLY BY API, 1220 L STREET, N.W., WASHINGTON, D.C. 20005. Copyright O 1993 American Petroleum Institute API PUBLr2558 93 0732290 0533879 T31 FOREWORD This publication was prepared for the American Petroleum Institute by the Cermak
8、Pe- terka Petersen, Incorporated. API publications may be used by anyone desiring to do so. Every effort has been made by the Institute to assure the accuracy and reliability of the data contained in them; however, the Institute makes no representation, warranty, or guarantee in connection with this
9、 pub- lication and hereby expressly disclaims any liability or responsibility for loss or damage re- sulting from its use or for the violation of any federal, state, or municipal regulation with which this publication may conflict. Suggested revisions are invited and should be submitted to Measureme
10、nt Coordination, American Petroleum Institute, 1220 L Street, N.W., Washington, D.C. 20005. . 111 API PUBLW558 93 0732290 0513880 753 W TABLE OF CONTENTS LISTOFAPPENDICES . LISTOFFIGURES LISTOFTABLES LISTOFSYMBOLS . 1.0 INTRODUCTION 2.0 BACKGROUND 2 . I Evaporative Loss Equation 2.2 Air Flow Around
11、Tanks 2.3 Wind Speea!s in the Atmosphere . 3.0 EXPERIMENTAL PROGRAM . 3.1 Simlarity Criteria 3.2 Model Construction . 3.3 Wnd Tunnel and Test Setup 3.4 Wind Direction 3.5 WindSpeed 3.6 Roof Pressures 3.7 Quality Control . 4.0 RESULTS . 4.1 General 4.2 WindSpeed 4.3 Wind Direction 4.4 Roof Top Pressu
12、res . 5.0 REVISED METHOD FOR CALCULATING EVAPORATION FROM ROOF FITTINGS . 5.1 General 5.2 Complex Method . 5.3 Simple Method 5.4 Discussion 6.0 CONCLUSION AND RECOMMENDATIONS . 7.0 REFEmNCES FIGURES TABLES . iii iv vi vii 1 3 3 5 6 9 9 9 10 10 11 12 13 15 15 15 16 16 19 19 19 21 22 25 27 31 65 V CPP
13、! A B C D E F G H I API PUBLu2558 93 O732290 0513881 b9T = LIST OF APPENDICES INSTRUMENTATION AND FACILITIES . A- 1 EXPERIMENTALMETHODS B- 1 TABLE OF PRESSURE COEFFICIENTS . c-1 PRESSURE COEFFICIENT PLOTS AT MEASUREMENT LOCATIONS . D- 1 PRESSURE COEFFICIENT CONTOURS BY WIND DIRECTION . E-1 WIND DIRE
14、CTION PHOTOGRAPHS . F-1 TABLE OF NON-DIMENSIONAL AND EQUIVALENT WIND VELOCITIES . G- 1 WIND ROSE OF NON-DIMENSIONAL AND EQUIVALENT WINDVELOCITIES . H- 1 NON-DIMENSIONAL MEAN VELOCITY CONTOURS I- 1 vi CPPH API PUBL*2558 93 0732290 0513882 526 LIST OF FIGURES la . Site Plan . 200 ft Tank b . Elevation
15、 . 200 ft Tank 2a . Site Plan . 100 ft Tank b . Elevation . 100 ft Tank 3a . Site Plan . 48 ft Tank . b . Elevation . 48 ft Tank . 4 . Velocity and Turbulent Approach Profiles . 5a . b . c . Wind Speed. Wind Direction and Roof Pressure Measurement Locations - 200 ft Tank Wind Speed. Wind Direction a
16、nd Roof Pressure Measurement Locations - 100 ft Tank Wind Speed. Wind Direction and Roof Pressure Measurement Locations - 48 ft Tank . 6a . b . c . Non-dimensional Mean Velocity Centerline Profiles . 200 ft Tank Nondimensional Mean Velocity Centerline Profiles . 100 ft Tank Non-dimensional Mean Velo
17、city Centerline Profiles . 48 ft Tank 7a . b . Average Non-dimensional Mean Velocity Contours . 200 ft Tank Average Nondimensional Mean Velocity Contours . 100 ft Tank Average Non-dimensional Mean Velocity Contours . 48 ft Tank . c . 8a . b . Roof Top Wind Directions Relative to Approach Flow . 200
18、ft Tank Roof Top Wind Directions Relative to Approach Flow . 100 ft Tank Roof Top Wind Directions Relative to Approach Flow . 48 ft Tank . c . 9a . b . c . Centerline Pressure Coefficient Profiles . 200 ft Tank . Centerline Pressure Coefficient Profiles . 100 ft Tank . Centerline Pressure Coefficien
19、t Profiles . 48 ft Tank 10a . b . c . Average Pressure Coefficient Contours . 200 ft Tank Average Pressure Coefficient Contours . 48 ft Tank Average Pressure Coefficient Contours . 100 ft Tank lla . b . Average Nondimensionai Mean Velocity Zones . 200 ft Tank Average Nondimensional Mean Velocity Zon
20、es . 100 ft Tank Average Non-dimensional Mean Velocity Zones . 48 ft Tank . c . 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 Vii API PUBLS2558 93 0732290 05l13883 4b2 LIST OF FIGURES (Continued) 12a. b . c. Average Non-dimensional Mean Velocity Centerline Profi
21、les - 200 ft Tank . 59 Average Nondimensionai Mean Velocity Centerline Profiles - 100 ft Tank . 60 Average Non-dimensional Mean Velocity Centerline Profiles - 48 ft Tank 61 API PUBLt2558 93 m 0732290 0513884 3T m LIST OF TABLES 1 . List of External Roof Fittings . 2 . Flow Visualization Test Plan 3
22、. Velocity Measurement Test Plan 4 . Pressure Measurement Test Plan 5 . Summary of Wind Directions on Tank Roof 6a . b . Evaporative Loss Example calculation . Complex Method RoofManway . Evaporative Loss Example Calculation . Complex Method Slotted Guide Pole 7 . Evaporative Loss Example Calculatio
23、n . Simple Method 65 66 69 70 71 72 73 74 ix CPPd API PUBL*Z558 93 m O732290 0533885 235 Svmbol D Ag) F H K L m M n N P* 4 r R LIST OF SYMBOLS DescriDtion Coefficient of Pressure Tank Diameter Frequency of Wind Direction Sector Evaporative Loss Factor Tank Height Product Loss Factor Stock Loss Evapo
24、rative Loss Factor Molecular Weight Wind Power Law Exponent Number of Fittings Vapor Pressure Function Dynamic Pressure Tank Radius Roof Height Average Wind Speed at fitting Reference Wind Speed Root Mean Squared Wind Speed at fitting Distance from Center of Tank Roof Surface Roughness Height Densit
25、y of Air Viscosity of Air X API PUBL*2558 93 = 0332290 05L388b 171 LIST OF SYMBOLS (Continued) Subscriut a airport e effective f fitting, full scale m model scale r rim seal S standing; site t total Y vapor xi API PUBL*2558 93 m 0732290 0513887 008 m Ce however, two of the topics which will be discu
26、ssed also apply to the rim seal loss equation. These include: 1) the comparison between roof top pressures measured in this study and previously published results from which F, was derived; and 2) the relationship between the site and the nearby airport wind speeds. The total roof fitting loss facto
27、r, Fp from Equation 3, can be expressed as the sum of the individual loss factors for each fitting. Section 2.2.2.2 of NI 2517 defines Ffas: k i=l where: Nf, = Number of type i roof fittings 4, = Loss factor for type i roof fitting (lb-mole/yr) k = Total number of different types of roof fittings an
28、d (4) where: Ki = Loss factor for type i roof fitting (Ib-mole/yr) Kbi = Loss factor for type i roof fitting (Ib-mole/mphVyr) mi = Loss factor for type i roof fitting e similar geometric dimensions; e equality of dimensionless boundary and approach flow conditions; where: u, = Ambient velocity at to
29、p of tank (ds) Hb = Tank height (m) va = Air viscosity (m2/s) 3.2 Model Construction Three 1 : 100 scale models of externa pontoon floating roof storage tanks were constructed. Each model included such details that are common to all pontoon storage tanks (stairs to tank roof, wind breakers around th
30、e perimeter of the tank, and rolling ladders). The appropriate number of roof fittings were modeled for each size tank as deemed typical for EFRT in Tables 6 and 7 of API 2517. The actual number of each fitting modeled, shown in Table 1, varied slightly from the prescribed values in some instances i
31、n order to maintain geometric symmetry. The overall API PUBL*2558 93 m 0732290 0533894 248 m Ce 2) Tank 2 - 48 ft height and 100 ft outside diameter; and 3) Tank 3 - 48 ft height and 48 fi outside diameter. Figures 1 through 3 provide site and elevation plans for the three tanks. The tanks were cons
32、tructed so that the roof could be adjusted to different heights. 3.3 Wind Tunnel and Test Setup Appendix A describes CPPs atmospheric wind tunnel and the instrumentation that was used to collect the data. in brief, a hot-wire anemometer was used to measure the wind speed and turbuience intensity, mi
33、niature wind vanes were used to document the wind direction, and mean and fluctuating pressures were obtained using differential pressure transducers. Prior to testing the tank models, a uniform roughness pattern was instailed in the wind tunnel upwind of the location where the tank models were plac
34、ed. The roughness was designed to simulate the roughness approaching a typical tank farm or industriai area (surface roughness length of 0.5 m). Mean velocity and turbulence intensity profiles were obtained using a hot-wire velocity sensor (see Appendix A for description) to ver that the profiles ma
35、tch those that would be observed in the atmosphere. The results of these profiles are shown in Figure 4. Different wind directions were tested, since some of the roof details (Le., stairs) will cause wind speeds to vary with wind direction at each point on the roof. Sixteen directions were selected
36、to be consistent with typical wind frequency distribution summaries provided by the National Weather Service so that the results can be readily used to compute average speeds and directions on the roof for a given site climatology. North (O degrees) was arbitrarily set for each tank as shown in Figu
37、res 1, 2 and 3 , such that the gaugers platform was positioned in the southeastern quadrant. 3.4 Wind Direction After the boundary layer approaching the model test area was documented, the tank models were installed, one at a time, in the wind tunnel. Initiai flow visualization tests were conducted
38、to develop a qualitative understanding of the flow over the tank roof. During the visualization tests, small flags were placed throughout the roof surface of the tanks at each of the measurement API PUBLJ2558 93 = 0732290 0533895 384 Ce calibration of velocity device with mass flow meter (see Append
39、ix B); calibration check between hot-wire and static pitot tube; calibration of pressure transducers with oil manometer (see Appendix B); comparison of wind tunnel velocity and turbulent intensity profiles with those observed in the atmosphere (see Figure 4); visual inspection of pressure data using
40、 X-Y plots of each measurement location to check data consistency (see Appendix E); API PUBLX2558 93 0732290 051389 993 Cennak Peterko Petersen, Inc. 14 CPP Project 92-0869 e visual inspection of velocity data using wind rose plots of each measurement location to check data consistency (see Appendix
41、 H). API PUBLX2558 93 = O732290 0533899 82T Cermuk Peterka Petersen, Inc. 15 CPP Project 92-0869 4.0 RESULTS 4.1 General The results of the pressure and velocity measurements collected during the course of this study are listed in Appendices C and G, respectively. Wind direction photographs are pres
42、ented in Appendix F for each data set configuration at the 16 wind directions. The pressure data is reported in terms of a pressure coefficient with the nearby NWS facility used as the reference wind speed for calculating the dynamic pressure. The velocity data has been nondimensionalized as a ratio
43、 of the measured velocity at each fitting divided by the corresponding approach wind speed at a nearby weather station. The following sections discuss the results in greater detail. 4.2 Wn Speed Roof top contours of the non-dimensional mean velocity data are included in Appendix I. The contours prov
44、ide a visual indication of the velocity distribution across the tanks. The recirculation region on each of the roof tops can be identified by large areas on the contour plots where the velocity is essentially constant. A comparison of the plots at different roof heights clearly depicts the growth of
45、 the recirculation region toward the downwind wall as the roof level is lowered. Figures 6 and 7 are presented as a summary to Appendix I. In Figures 6a, b and c centerline velocity profiles are shown for each of the three tanks at the three roof levels. The three sets of curves depict the relative
46、magnitude of the wind speed over the fittings from the leading edge of the tank, across the centerline, to the downwind edge of the tank. In Figures 7a, b and c the average velocity contours for the three tanks is depicted. The average contours were obtained using the average mean velocity measured
47、at each point for the 16 wind directions. The API literature provides no direct comparison for the centerline velocity profiles shown in Figures 6a, b and c. However, a review of the three sets of profiles produce rather interesting results. For all three tanks the wind speed across the roof top is
48、consistently higher when the API PUBL*2558 93 m O732290 O533900 Cermuk Peterka Petersen, Inc. 16 roof is at tank height level than it is when the roof is lowered to 373 m CPP Project 92-0869 the intermediate level. This trend does not persist when the roof top is further lowered to the lowest roof h
49、eight. At this level, the velocities are generally greater than at the mid-level roof height. (A possible explanation for this behavior is presented in Section 4.3.) Figures 6b and c indicate that in certain areas the wind speeds at the lowest height actually exceed those measured at the tank top level. If the velocity field of the EFRT roofs were independent of wind direction, each of the contours shown in Figures 7a, b and c would consist of concentric circles. It can be noted from the figures that overail the flow is fairly symmetric except for an area near the rolling ladder whe
