1、 AEROSPACE RECOMMENDED PRACTICE Droplet Impingement and Ice Accretion Computer Codes Issued 2003-10 ARP5903 TABLE OF CONTENTS 1. SCOPE 3 1.1 Background3 1.2 Purpose3 2. REFERENCES.4 2.1 Applicable Documents .4 2.2 Applicable References .5 2.3 Definition of Selected Terms6 2.4 Abbreviations .9 2.5 Sy
2、mbols .10 3. INTRODUCTION TO DROPLET IMPINGEMENT AND ICE ACCRETION CODES10 3.1 Elements of Droplet Impingement and Ice Accretion Codes10 3.2 Survey of Current Droplet Impingement and Ice Accretion Simulation Software.13 4. DROPLET IMPINGEMENT AND ICE ACCRETION CODE APPLICATIONS14 4.1 Uses of Droplet
3、 Impingement and Ice Accretion Codes 15 5. COMPARISON PARAMETERS.22 5.1 Parameter List23 5.2 Definition Sources24 5.3 Clarification of Parameter Definitions.24 5.4 Organization Comments on Parameter Ranking .25 Reaffirmed 2009-12SAE Technical Standards Board Rules provide that: “This report is publi
4、shed by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefrom, is the sole responsibility of the user.” SAE reviews each technical
5、 report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright 2009 SAE International All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any for
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7、ww.sae.org SAE values your input. To provide feedbackon this Technical Report, please visit http:/www.sae.org/technical/standards/ARP5903Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP5903 -
8、2 - 6. GUIDELINES FOR THE USE OF DROPLET IMPINGEMENT AND ICE ACCRETION CODES 26 6.1 Overview 26 6.2 Icing Code Applications28 6.3 Icing Code Selection 35 7. SOFTWARE ADMINISTRATION .40 7.1 Recommended Software Practices For Code Developers.40 7.2 Recommended Software Practices for Code Users.42 8. N
9、OTES.43 APPENDIX A BASIC INFORMATION ON EXISTING ICE ACCRETION COMPUTER CODES .44 APPENDIX B EXAMPLE OF METHODOLOGY FOR APPLICATION OF AN ICE ACCRETION COMPUTER CODE FOR TRAJECTORY CALCULATIONS85 Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or netwo
10、rking permitted without license from IHS-,-,-SAE ARP5903 - 3 - 1. SCOPE: This document provides information, guidelines, and practices for the application, use, and administration of two-dimensional and three-dimensional droplet impingement and ice accretion computer codes. The codes provide computa
11、tional simulations of inflight icing that predict droplet trajectory, water loading, and ice accretion on aircraft components. These ice accretion characteristics are used during the aircraft design and certification process. 1.1 Background: The U.S. Federal Aviation Administration established an ic
12、ing plan in 1997 to respond to a need for a comprehensive program to create an awareness of inflight icing issues and to establish documents to provide training and guidance for regulatory authorities, aircraft operators, research organizations, and aircraft manufacturers. The FAA published a 14-tas
13、k plan, entitled the “FAA Inflight Aircraft Icing Plan,” and identified groups of people within the U.S. Government and throughout the aircraft industry to address the action items contained in this plan. Task 11 of this plan called for the development of “validation criteria and data for simulation
14、 methods used to determine ice shapes on aircraft.” It also indicated that this task was to include data on “wind tunnels, ice accretion computer codes, and icing tankers.” The FAA suggested “a coordinated effort among research organizations, industry, and regulatory authorities” and individuals wer
15、e asked to participate in this work. Task 11 was divided into three subtasks and the people that participated in Subtask A were tasked with addressing criteria for the use of tankers, tunnels, and codes. Three documents were developed by the members of the Task 11A Working Group and these three docu
16、ments are being published as SAE ARPs. While each document follows a format that is appropriate to the topic, the three documents provide guidance for the application of codes (ARP5903), tankers (ARP5904), and tunnels (ARP5905) to the icing certification or qualification process. 1.2 Purpose: The pu
17、rpose of this document is to provide a resource for industry and certification authorities relative to the capabilities and uses of droplet impingement and ice accretion computer codes. As with any tool, the use of droplet impingement and ice accretion codes requires some judgment on the part of the
18、 user as to whether the code is appropriate for the intended use. This document provides information, guidelines, and practices with respect to the use of these tools. These codes, when used properly, can provide the designer and airworthiness authorities with useful information about water loading
19、and ice growth on aircraft components, and on other phenomena associated with the ice growth process. This document describes practices used by code developers for the creation and documentation of droplet impingement and ice accretion codes and practices used by aircraft and component manufacturers
20、 when employing these codes for the design and certification or qualification of their products. Applications of these codes are described. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP5903
21、 - 4 - 1.2 (Continued): Since other practices exist or may be developed in the future, these guidelines and practices are not considered all inclusive nor are certification authorities compelled to accept implementation of these guidelines and practices as part of an aircraft certification program.
22、2. REFERENCES: 2.1 Applicable Documents: The following publications form a part of this document to the extent specified herein. The latest issue of SAE publications shall apply. The applicable issue of other publications shall be the issue in effect on the date of the referencing document. In the e
23、vent of conflict between the text of this document and references cited herein, the text of this document takes precedence. Nothing in this document however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 2.1.1 SAE Publications: Available from SAE, 400 Comm
24、onwealth Drive, Warrendale, PA 15096-0001. AIR5504 Aircraft Inflight Icing Terminology AIR5906 Ice Shape Measurement and Comparison Techniques Workshop ARP5904 Airborne Icing Tankers ARP5905 Calibration and Acceptance of Icing Wind Tunnels 2.1.2 U.S. Government Publications: Available from DODSSP, S
25、ubscription Services Desk, Building 4D, 700 Robbins Avenue, Philadelphia, PA 19111-5094. FAA Reports (Documents with numbers such as DOT/FAA/AR-00/37 or DOT/FAA/CT-88/8-3) are available through the National Technical Information Service (NTIS), Springfield, VA. FAA Regulations: Superintendent of Doc
26、uments, U.S. Government Printing Office,Internet: bookstore.gpo.gov, Phone: (202)512-1800, Fax: (202)512-2250, Mail: Stop SSOP, Washington DC 20402-0001. Advisory Circulars: U.S. Department of Transportation, Subsequent Distribution Office, SVC-121.23, Ardmore East Business Center, 3341 Q 75th Avenu
27、e, Landover, MD 20785. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP5903 - 5 - 2.1.2 (Continued): - “FAA Inflight Aircraft Icing Plan,“ United States Department of Transportation, Federal A
28、viation Administration, April 1997. - U.S. Standard Atmosphere, National Oceanic and Atmospheric Administration, National Aeronautics and Space Administration and United States Air Force. AC 20-73 U.S. Department of Transportation, Federal Aviation Administration Advisory Circular, Aircraft Ice Prot
29、ection, April 21, 1971. ADS-4 Engineering Summary of Airframe Icing Technical Data, FAA Technical Report ADS-4, March 1964. CFR 14 Part 23 Title 14 of the US Code of Federal Regulations, Part 23, Airworthiness Standards, Normal, Utility, Acrobatic, and Commuter Category Airplanes. CFR 14 Part 25 Tit
30、le 14 of the US Code of Federal Regulations, Part 25, Airworthiness Standards, Transport Category Airplanes. CFR 14 Part 29 Title 14 of the US Code of Federal Regulations, Part 29, Airworthiness Standards, Transport Category Rotorcraft. CR-1999-208690 Validation Results for LEWICE 2.0, NASA CR-1999-
31、208690, January 1999. DOT/FAA/CT-88/8 Aircraft Icing Handbook, Volumes 1, 2 and 3, DOT/FAA/CT-88/8, March 1991 and subsequent revisions. 2.2 Applicable References: Anderson, D. N., Hentschel, D. B. and Ruff, G. A., “Measurement and Correlation of Ice Accretion Roughness,” AIAA-98-0486, 36th Aerospac
32、e Sciences Meeting, Reno, NV, January 1998. Ruff, G. A., “Automated Comparison of Ice Accretion Shapes,” Paper No. AIAA-99-0625, 37th Aerospace Sciences Meeting, Reno, NV, January 1999. AVT RTO-TR-038, “Ice Accretion Simulation Evaluation Test,” NATO RTO, November 2001. Wright, W.B., and Rutkowski,
33、A., “Validation Results for LEWICE 2.0,“ NASA CR-1999-208690, January 1999. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP5903 - 6 - 2.3 Definition of Selected Terms: The following terms are
34、 used in this document. Additional clarification on the meaning of some terms is given in 5.3. The SAE Aircraft Inflight Icing Terminology AIR is a resource for the definition of additional icing terms. 2.5 DIMENSIONAL: Any method that combines 2D and 3D calculation procedures. ANTI-ICING: The preve
35、ntion of ice formation or accumulation on a protected surface, either by evaporating the impinging water or by allowing it to run back and off the surface or freeze on non-critical areas. APPENDIX C ICING ENVELOPES: The 14 CFR Parts 25 and 29, Appendix C icing envelopes for continuous maximum and in
36、termittent maximum icing conditions. COLLECTION EFFICIENCY: See water catch efficiency. EULERIAN DROPLET TRAJECTORY COMPUTATION: A method for calculating the dynamics of the forces exerted on water droplets in the surrounding airflow using a frame of reference that is fixed in space. Thus, the mass
37、flux into and out of a region in space is the outcome of this approach. This approach typically results in equations describing the mass flux through a control volume. These equations are also in a form that is compatible with solution methods normally employed for grid based flowfield codes. FREEZI
38、NG FRACTION: The fraction of liquid water that freezes in a given control volume. ICE CROSS-SECTIONAL AREA: The integral of y with respect to x for the iced coordinates minus the same integral for the clean airfoil (see Equation 1). g11 g12 g11 g12iced cleaAydx ydxg32g16g212g212(Eq. 1) ICE SHAPE DET
39、ERMINATION: Determination of resultant ice shape by computational analysis. ICING LIMIT: The location farthest aft on a body at which ice accretes. This distance can be measured either as the x distance from the leading edge or as the surface distance from the stagnation point. In this document the
40、icing limit is defined as the x distance from the leading edge. IMPINGEMENT LIMIT: The location farthest aft on a body at which water droplets impinge on either the upper or lower surface. This distance can be measured either as the x distance from the leading edge or as the surface distance from th
41、e stagnation point. In this document the impingement limit is defined as the x distance from the leading edge. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP5903 - 7 - 2.3 (Continued): INVIS
42、CID CODE: A code that assumes a zero coefficient of viscosity and, therefore, does not include the effects of fluid shear stresses so that the flow velocity at the surface boundary is the same as the flow velocity of the freestream. LAGRANGIAN DROPLET TRAJECTORY COMPUTATION: A method for calculating
43、 the dynamics of the forces exerted on water droplets in the surrounding airflow using a frame of reference that is fixed on the droplet. These trajectories are typically calculated by determining the forces exerted on individual droplets and then determining the resulting motion of the droplet. The
44、 calculation proceeds by sequentially calculating forces and resulting motion as the droplet moves through the flowfield surrounding the body of interest (i.e., the wing, fuselage, engine inlet, etc.) until it either impacts on the body or passes it. LIQUID WATER CONTENT: The mass of water contained
45、 in liquid cloud droplets within a unit volume of cloud, usually given in units of grams of water per cubic meter of air (g/m3). LOWER HORN ANGLE: The angle of the lower horn of a glaze ice shape, calculated with the polar direction of 0 being a right-facing horizontal line (see Figure 1). Several a
46、pproaches have been proposed for the origin of the first line segment, which is the line from some point on or inside of the airfoil to the tip of the horn. The first line segment can be measured from the tip of the horn to a fixed reference point at the leading edge (as shown in Figure 1) or near t
47、he leading edge, or the first line segment can be measured from the tip of the horn to a fixed reference point at the center of the inscribed circle at the leading edge (defined by the leading edge radius for the airfoil). The second line segment is the horizontal line intersecting the reference poi
48、nt. FIGURE 1 Definition of Lower and Upper Horn Angle Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP5903 - 8 - 2.3 (Continued): MEDIAN VOLUME DIAMETER: The droplet diameter, usually given in
49、 microns (10-6m), such that one-half the liquid water is contained in droplets smaller than the median volume diameter and one-half the liquid water is contained in droplets larger than the median volume diameter. MULTI-STEP ICE ACCRETION PROCEDURE: A time-stepping procedure to “grow“ the ice accretion; a procedure that calculates the amount of ice accu
