1、_ 6$(7HFKQLFDO6WDQGDUGV%RDUG5XOHVSURYLGHWKDW7KLVUHSRUWLVSXEOLVKHGE6$(WRDGYDQFHWKHVWDWHRIWHFKQLFDO 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 tKHUHIURPLVWKHVROHUHVSRQVL
2、ELOLWRIWKHXVHU SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2014 SAE International All rights reserved. No part of this publication may be reproduced, st
3、ored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-4970 (outside USA) Fax: 724-776-079
4、0 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/ARP8058 AEROSPACERECOMMENDED PRACTICE ARP8058 Issued 2014-06 Thermal Design and Performance of Airplane In-Flight
5、 Food Storage Carts RATIONALE The design of the in-flight food storage (galley) cart and its interface with the airplane galley cooling system are important for maintaining the thermal environment necessary for keeping food and beverages in a safe and high-quality condition. This document provides d
6、esign guidance, performance criteria, and test methods to ensure that the galley cart exhibits the characteristics necessary to comply with this thermal requirement. TABLE OF CONTENTS 1. SCOPE 3 1.1 Purpose . 3 2. REFERENCES 3 2.1 Applicable Documents 3 2.1.1 SAE Publications . 3 2.2 Definitions . 3
7、 2.3 Mandating and Recommending Phrases 3 3. GENERAL REQUIREMENTS . 4 3.1 Cart Design . 4 3.1.1 Dry-Ice Carts . 4 3.1.2 Air-Through Carts . 4 3.1.3 Air-Over Carts . 6 4. PERFORMANCE REQUIREMENTS 7 4.1 Thermal . 7 4.2 Leakage 7 5. TESTING . 7 5.1 Warm Air Test . 75.1.1 Test Set-up 7 5.1.2 Test Proced
8、ure 9 5.1.3 Acceptance Criteria . 9 6. PERIODIC MAINTENANCE . 9 7. NOTES 9 APPENDIX A HEAT TRANSFER COEFFICIENT SAMPLE CALCULATIONS 10 SAE INTERNATIONAL ARP8058 Page 2 of 11 FIGURE 1 DRY ICE COOLING FOR CARTS 4 FIGURE 2 AIR-THROUGH COOLING FOR CARTS . 5 FIGURE 3 THE REAR FACE OF THE AIR-THROUGH CART
9、S . 6 FIGURE 4 AIR-OVER COOLING FOR CARTS . 7 FIGURE 5 WARM AIR TEST SETUP 8 FIGURE 6 TEMPERATURE SENSOR LOCATIONS . 8 SAE INTERNATIONAL ARP8058 Page 3 of 11 1. SCOPE This SAE Aerospace Recommended Practice (ARP) provides design guidance and a method for testing thermal performance of airplane in-fl
10、ight food storage carts. It is noted that thermal performance criteria is not part of AS8056. 1.1 Purpose The objective of airplane galley refrigeration systems is to maintain food at temperatures at which harmful bacterial growth is minimized. National health safety regulations that once allowed fo
11、od to be stored at 45 F (7 C) have been improved and now call for food storage at temperatures below 39.2 F (4.0 C) (Europe) and 41 F (5 C) (USA). Airplane in-flight food storage carts are a critical part of the overall galley refrigeUDWLRQVVWHPWKHUHIRUHDVVXULQJWKDWDFDUWVthermal characteristics supp
12、ort this goal is essential. The requirements prescribed herein are directed toward this goal. 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
13、 publications shall be the issue in effect on the date of the purchase order. In the event 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 spe
14、cific exemption has been obtained. 2.1.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org. ARP695 Galley System Design and Installation Criteria AS8056 Minimum De
15、sign and Performance of Airplane Galley In-Flight Carts, Containers, and Associated Components 2.2 Definitions CART: A movable enclosure on wheels designed for the purpose of transporting and storing various items used for cabin service activities. A Cart is typically pushed up and down the airplane
16、 passenger aisles during cabin service activities. INTERFACE: The fit and functional relationships of the cart with the galley or other structure (e.g., ducts). INTERFACE CONTROL DRAWING (ICD): An engineering drawing created for the purpose of communicating interface information. 752/(7KHZRUGWUROOHL
17、VVQRQPRXVZLWKFDUW 2.3 Mandating and Recommending Phrases 7KHZRUGVKDOOLQGLFDWHVDPDQGDWRUFULWHULRQ 7KH ZRUG VKRXOG LQGLFDWHV D FULWHULRQ IRU ZKLFK DQ DOWHUQ ative, including noncompliance, may be applied if it is documented and justified. SAE INTERNATIONAL ARP8058 Page 4 of 11 3. GENERAL REQUIREMENTS
18、3.1 Cart DesignThe temperature in a galley cart is typically maintained either by dry ice placed inside the cart or by chilled air circulating over and around or through the cart. Each approach imposes specific design and performance requirements for the cart. 3.1.1 Dry-Ice Carts &RROLQJLVSURYLGHGEV
19、XEOLPDWLRQRIGULFHLQDVHSDUDWHGULFHFRQWDLQHU7KHFDUWVGULFHFRQWDLQHUVKRXOGEHORFDWHG at the top of the cart to achieve downward cold air flow. The ice container shall be made from an insulated material and tightly constructed/sealed such that cold air flows out its intended air delivery hole(s) only. The
20、 insulated material should be selected to have a low heat transfer rate (e.g., be non-metallic) as this reduces conduction through the container and increases natural convection (see Figure 1). Reducing conduction through the container reduces the potential for freezing food located nearby (upper fo
21、od storage positions) and reduces cooling loss to unintended areas (e.g., loss to the ambient environment). Dry IceFood PackagesNon-Conductive Air FlowAir Flow HoleAir Flow HoleInsulated MaterialFIGURE 1 - DRY ICE COOLING FOR CARTS 3.1.2 Air-Through Carts Cooling is provided by chilled air flowing i
22、nto the cart. This cart has air inlet and outlet grills located in the back. Cold air IURPDQHWHUQDOVRXUFHIORZVWKURXJKWKHLQOHWJULOOFRPHVLQGLUHFWFRQWDFWZLWKWKHFDUWVFRQW ents and returns to the source through the outlet grill. Figure 2 illustrates an air chiller as the external source of cold air, whic
23、h flows through galley ducting into the cart and then returns to the air chiller. SAE INTERNATIONAL ARP8058 Page 5 of 11 FIGURE 2 - AIR-THROUGH COOLING FOR CARTS The back of the cart shall have one air inlet opening and one air outlet opening (see Figure 3). Service history has shown that a cart wit
24、h openings dimensioned and positioned as described below can be successfully integrated into the refrigeration system: a. The air inlet is 4.0 inches x 4.0 inches (H x W) (100 mm x 100 mm), with the center of the opening located 32 inches (812.8 mm) above and along the centerline of the cart bottom
25、panel. b. The air outlet is 4.0 inches x 4.0 inches (H x W) (100 mm x 100 mm), with the center of the opening located 10 inches (254 mm) above and along the centerline of the cart bottom panel c. The inlet and outlet locations assume the cart bottom panel is approximately 4.0 inches (100 mm) above t
26、he airplane floor. d. The air inlet and air outlet openings are covered with a grill (minimum 16 holes per inch). e. The surface around the inlet and outlet openings is flat and smooth, extending at least 0.75 inches (19 mm) from the entire outer edge of the opening as shown in Figure 3. SAE INTERNA
27、TIONAL ARP8058 Page 6 of 11 FIGURE 3 - THE REAR FACE OF THE AIR-THROUGH CARTS 3.1.3 Air-Over Carts Cooling is provided by chilled air from an external source flowing around the outside of the cart, which is stowed in an enclosed compartment. Figure 4 illustrates an air chiller as the external source
28、 with cold air flowing through galley ducting into an enclosed galley compartment, circulating around the outside of the cart before returning to the air chiller. SAE INTERNATIONAL ARP8058 Page 7 of 11 FIGURE 4 - AIR-OVER COOLING FOR CARTS 4. PERFORMANCE REQUIREMENTS 4.1 Thermal The enclosure of the
29、 cart shall be designed to have a heat transfer coefficient (U-value) equal to or less than 0.005 BTU/hour-square inch-F when tested per Section 5. 4.2 Leakage All carts shall be designed and maintained to ensure doors and dry ice drawers seal tightly against their frames. 5. TESTING 5.1 Warm Air Te
30、st The Warm Air Test shall be used to determine the Heat Transfer Coefficient (U-value). The U-value demonstrates the thermal characteristics (i.e., insulation and air leakage) of the cart. 5.1.1 Test Set-up a. Set a fan on the interior floor of the cart as shown in Figure 5. The purpose of the fan
31、is to provide a small amount of airflow so that a uniform temperature distribution is achieved inside the cart. The fan shall not generate more than 5% of the rated heat load in order to keep the heat load constant. b. Place a known and constant heat load source (typically a 100 to 200 W incandescen
32、t light bulb) inside the cart. c. Place at least three (3) temperature sensors inside the cart. These inside sensors are used to obtain the average inside temperature TIN. The temperature sensors shall be located a minimum of 6 inches (152.4 mm) from the heat source and the fan and a minimum of 3 in
33、ches (76.2 mm) from cart interior surfaces to ensure accurate measurement of air temperature (see Figure 6). SAE INTERNATIONAL ARP8058 Page 8 of 11 d. Place at least two (2) temperature sensors outside the cart, at a minimum distance of 6 inches (152.4 mm) from its exterior surfaces. These outside s
34、ensors measure the ambient air temperature surrounding the cart and are used to obtain the average outside temperature TOUT (see Figure 6). e. For air-through carts, seal the air inlet and outlet openings. FIGURE 5 - WARM AIR TEST SETUP FIGURE 6 - TEMPERATURE SENSOR LOCATIONS SAE INTERNATIONAL ARP80
35、58 Page 9 of 11 5.1.2 Test Procedure a. Turn on the light bulb and fan, close the cart door(s), and wait until the temperature differential between the interior (warmer air) and exterior of the cart stabilizes (less than 2 F fluctuation in 5 minutes). b. Measure and record the temperature from each
36、sensor. c. Determine the average inside temperature TIN and the average outside temperature TOUT as follows: TIN = the average of the inside temperature sensor readings TOUT = the average of the outside temperature sensor readings d. Calculate the heat transfer coefficient (U-value) using the follow
37、ing formula: (Eq. 1) where: Q = Constant heat load, Watt (or BTU/hour) from light bulb. 100% of the bulb rating is assumed to be heat for this calculation as empirical testing showed this provides sufficient accuracy. A = Total exposed surface area of the cart, m2 (or square inch) based on the inter
38、ior height, width, and depth of the cart. U = Heat Transfer Coefficient, W/m2-C (or BTU/hour-square inch-F) 5.1.3 Acceptance Criteria The measured heat transfer coefficient (U-value) shall be equal to or less than 0.005 BTU/hour-square inch-F. 6. PERIODIC MAINTENANCE Maintenance of in-service carts
39、shall include repair or replacement of the following, as is necessary to maintain an acceptable U-value: a. Door and gap seals b. Door alignment and fitc. Air grills 7. NOTES 7.1 A change bar (l) located in the left margin is for the convenience of the user in locating areas where technical revision
40、s, not editorial changes, have been made to the previous issue of this document. An (R) symbol to the left of the document title indicates a complete revision of the document, including technical revisions. Change bars and (R) are not used in original publications, nor in documents that contain edit
41、orial changes only. PREPARED BY SAE COMMITTEE S-9, CABIN SAFETY PROVISIONS SAE INTERNATIONAL ARP8058 Page 10 of 11 APPENDIX A - HEAT TRANSFER COEFFICIENT SAMPLE CALCULATIONS How to solve for A W = Width of interior wall of cart D = Depth of interior wall of cart H = Height of interior wall of cart E
42、xample: Typical Full Size Cart Interior Dimensions: W = 10.75 inches D = 31.0 inches H = 33.5 inches Constant Heat Load Temperature Difference After 90 minutes of Stabilization (less than 2 F fluctuation in 5 minutes). , T1 = 100.0 F, T2 = 101.0 F, T3 = 102.0 F T4 = 73.5 F, T5 = 72.5 F , , SAE INTERNATIONAL ARP8058 Page 11 of 11 Solve for U (Heat Transfer Coefficient) Acceptance Criterion:
