DOCSLIB.ORG

Standard Materials May Be Used in Concert Hall Construction, but for Acoustical Reasons They Are Often Handled in Special Ways

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Standard Materials May Be Used in Concert Hall Construction, but for Acoustical Reasons They Are Often Handled in Special Ways Concert Standard materials may be used in concert hall construction, but for acoustical reasons they are often handled in special ways. Halls by David McCandless Specifying for Sound Performance To some designers and specification separated. One discipline is the design writers it may seem strange to think of the auditorium itself: the volume, of all concert hall construction shaping, finishes, and furnishings materials as “acoustical” materials, necessary to achieve the best but such is the case. All interior wall, acoustical environment for the natural floor, and ceiling surfaces, and all (unamplified) sounds of musical finishes and furnishings have an instruments. This discipline is called effect on the acoustical environment “room acoustics.” in which concerts are performed. In If it is a place for listening, a big addition, the way the hall is con- room's acoustical environment is its structed and the design of the HVAC hallmark. For a concert hall, “good system play a part in eliminating acoustics” involves noise disturbance during a concert. • good distribution of sounds to all Standard materials may be used, but the seats, which depends on proper for acoustical reasons they are often shaping and finishes of all interior handled in special ways. surfaces In concert hall acoustics design • natural sound diffusion and there are two basic disciplines—room envelopment acoustics and noise control—whose • a sense of intimacy for the audi- needs and solutions are different, ence and a sense of ensemble for both though they must often be achieved in musicians and audience the same wall, floor, or ceiling detail. • proper reverberation times Sometimes the same materials are throughout all frequencies, which used for different reasons, and their depend on the room's volume and the materials' specifications are similarly total sound absorption of all materials The two acoustical disciplines: room acoustics and noise control. • freedom from the acoustical acoustics have been established. The that shape will be hard, sound- faults of echoes, flutter, and focus floor, wall, and ceiling structures reflective materials, individually • freedom from disturbing noises enclosing that envelope must then be described further in the specifications. Many halls in which classical designed to achieve the necessary Some typical hard materials and music is performed have proscenium noise control. The design process relevant room acoustics concerns are stages, lofts, and backstage areas used must recognize the two acoustical described below. when other types of programs are disciplines throughout the project's Plaster. Plaster is a traditional presented. Symphony concerts in creative and construction document material for ceilings and walls in these halls usually require special phases. concert halls. It is used in large areas orchestra shells designed to put the The degree of noise control re- and on broad surfaces, as well as in orchestra in the same room with the quired is usually set when the room specially shaped details. Plaster is audience, eliminating sound energy acoustics criteria are established. usually used with extra thickness—up loss and late arrival of sounds from Typically, the allowable background to 1½ to 2 inches—because the the back of the stage. Halls planned (ambient) noise levels are set at Noise stiffness and mass are necessary to for concert programs only, such as Criterion 25 (NC-25), a single resist panel vibration, which causes Boston's Symphony Hall, among number rating representing a series of low frequency absorption, and to many others, have a platform for the allowable levels across eight octaves achieve good reflections at all orchestra in the same room with the of the hearing range. Sometimes an frequencies. Since the necessary audience, without any backstage, loft, even lower Noise Criterion is used, stiffness requires more mass than is or proscenium arch. especially where sound recording is typical in most of today's building “Noise control,” the elimination of anticipated. While the NC levels are details (gypsum board, for example), distracting sounds from the concert used most specifically for controlling a stronger supporting structure may hall, is the other basic discipline in noise from the HVAC systems, they also need to be specified. auditorium acoustics. The typical are also used as a basis for controlling The acoustics of a concert hall require sources of disturbing noises are other other transmitted noises. These very diffuse reflections throughout activities within the building; the controls must be developed in relation the room. To enhance the reverber- building's mechanical systems; and to each other so that the total of ance and give a sense of sound airplanes, trains, and other traffic transmitted noises through the room's envelopment, the side walls and outside the building. envelope and through the HVAC sometimes the ceiling are often When the proper “envelope” (the system together do not exceed the shaped to scatter sounds. Plaster is room's shape and volume) has been design criteria. often used to create these shapes, designed, with the proper interior which may be large architectural finishes and furnishings, the room “Hard” Acoustical Finishes and forms or smaller decorative and Furnishings functional forms. Many of the DAVID McCANDLESS, AIA, is direc- The volume and shape of a concert architectural shapes used in concert tor of architectural acoustics for Jack hall are established in the drawings hall interior surfaces are repeated Evans & Associates, Inc., an acousti- and details in a project's contract enough to permit precasting. This cal consulting firm in Austin, Texas. documents. Most of the surfaces of casting is often done in fiberglass- Reprinted by permission The Construction Specifier, April 1990 The two disciplines in a typical detail. reinforced gypsum (FRG). When framing, they are stressed so that they large, flat surfaces of FRG are cannot vibrate diaphragmatically. So designed, they must be specified to be bent, they are as stiff as thick plaster, stiff like thick plaster. and will not exhibit much low Gypsum board. Gypsum board is frequency absorption unless the seldom used in concert hall design whole curved system is not rigidly concern. Small glass decorative because it has too much low fre- supported. elements might actually provide some quency absorption resulting from Masonry. Masonry materials such useful sound diffusion. natural panel vibration in response to as stone, brick, block, and concrete sound pressure pulses. When gypsum usually are thick and massive enough “Soft” Acoustical Finishes and Furnishings board is used in walls and ceilings, as to reflect low frequencies. Some in civic auditoriums and most porous, precast masonry units, The people attending a concert churches, the designer should specify however, absorb middle and upper probably constitute the most absorp- double layers of ⅝-inch-thick gypsum frequencies due to their porosity; if tive surface in a concert hall. The board, laminated for stiffness and used over large areas these materials other absorptive surfaces will be the installed on a furring system designed will significantly affect the reverbera- treatments for controlling echoes, and with extra stiffness. tion times of the room. The porosity sound foci from rear walls, balcony Wood and wood paneling. can be sealed and painted, of course, faces, and similar surfaces. These Wood, often used in concert hall but only on the recommendation of an areas must be limited, however, or design for aesthetic reasons, must be acoustical consultant who has else the room could become too installed with care. Thin wood assessed all finishes and furnishings “dead”—not “live” enough to give the paneling with air space behind it (i.e., in the room. music the desired reverberance. on furring) will allow unwanted low Metals and metal paneling. In Since the audience is the major frequency absorption through panel addition to absorbing low frequencies, sound absorber, comparing the room vibration—much as thin plaster and diaphragmatic movement of metal volume to the number of seats gypsum board do. Such paneling must materials might also cause rattles, so planned is useful. The reverberation be backed with solid construction they, too, should be laminated to solid time in the room is related directly to such as plaster or thick gypsum board, core material. the volume of the room and, in- to which it can be laminated. Large Glass. Glass is seldom used in versely, to the total sound absorption areas—and small surfaces repeated concert halls, since these rooms are in the room. The volume/seat ratio enough to be acoustically signifi- usually internal spaces surrounded by that has been found to be appropriate, cant—require this treatment. Solid public hallways and functional through comparison of many good wood used in moldings and other spaces, and because windows could symphony halls, can range from 250 details usually is not a concern; in be a path of unwanted noise transmis- to 350 cubic feet per seat. This is only fact, it may make the paneling stiffer. sion. Glass might be used for a rule of thumb for room size, When plywood and gypsum board decorative design and lighting, but however. Proper sound distribution, are bent over curved wall or ceiling only large, flat areas would be of diffusion, envelopment, intimacy, and Reprinted by permission The Construction Specifier, April 1990 Sound Transmission Class (STC). A single-number rating system for barrier constructions for full-frequency performance in laboratory testing. Two stud walls shown. the right reverberation times must still be achieved, along with freedom from noise disturbance, echoes, focus, and flutter. Some of the typical, soft (absorptive) materials used, and their relevant concerns in concert halls, are described below. Seating. Seating absorption should match the absorption of people so that when people are absent, as in rehearsals and low attendance, there will not be a noticeable change in the reverberation times of the hall. Designers should specify seats upholstered on the cushion and back rest, and possibly on the rear of the seat back.
Load more

Recommended publications
  • Sharing a House but Not a Household: Extended Families and Exclusionary Zoning Forty Years After Moore
    SHARING A HOUSE BUT NOT A HOUSEHOLD: EXTENDED FAMILIES AND EXCLUSIONARY ZONING FORTY YEARS AFTER MOORE Solangel Maldonado* INTRODUCTION Moore v. City of East Cleveland1 is undeniably a victory for extended families that do not conform to the nuclear family form because the state can no longer prevent them from living together in one household. In particular, it is a victory for families of color, immigrants, and economically vulnerable families who are more likely to reside with extended family members for cultural and economic reasons. Justice Lewis Powell, writing for the plurality, recognized the American tradition of extended family members living in one household,2 and Justice William Brennan (joined by Justice Thurgood Marshall) further noted that the extended family “remains not merely still a pervasive living pattern, but under the goad of brutal economic necessity, a prominent pattern—virtually a means of survival— for large numbers of the poor and deprived minorities of our society.”3 Like most decisions, however, Moore is not without its critics. As my students point out each year, the Court’s distinction between the City of East Cleveland’s narrow definition of a family and ordinances that allow anyone who is related by blood, marriage, or adoption to live together in a single-family household4 suggests that the Moore Court would exclude de facto parents, cohabiting partners, or close friends sharing a home from its definition of family. A definition of family that requires blood, marriage, or adoption is unnecessarily narrow and is not consistent with modern conceptions of family. * Professor of Law, Seton Hall University School of Law.
    [Show full text]
  • Arch Hall: from Alexandria to Fairfax to Street Name
    Office of Historic Alexandria City of Alexandria, Virginia Out of the Attic Arch Hall: from Alexandria to Fairfax to street name Alexandria Times, May 26, 2011 Image: Arch Hall, 815 Franklin Street, around 1937. Photo, Library of Congress. riginally located on Franklin Street between South Columbus and South Alfred streets, the home known as Arch O th Hall was built in the late 18 century. It served as a town residence for Lewis Lawrence, his wife Nelly Parke Custis, and their children when they stayed in Alexandria and not at Woodlawn, their large estate near Mount Vernon. The house, initially a one-story frame structure measuring 24 feet by 50 feet, had an attached frame kitchen at the east end. The front elevation faced south and had five bays. The center doorway had an arched transom and sidelights, and the center hallway had an arched ceiling. Later expansion included a lowered basement and renovation of the attic which resulted in relocation of the chimney. Arch Hall had several owners and tenants after being sold out of the Lawrence Lewis family. In the early 1930s, it was the site of Arch Hall Antiques but shortly after this photograph was taken around 1937, new owners, the Swetnams, restored the property and modernized it, installing a hot water heater, an oil furnace and new kitchen appliances. After the restoration was complete, Arch Hall became a popular stop on local historic home tours. In the fall of 1950, the structure was removed from its location at 815 Franklin Street, and over the next year, it was reconstructed at a new location near Belmont Bay in Fairfax County.
    [Show full text]
  • J. HALL HOMES , INC. Custom Residential Homebuilder Has a Reputation for American Builders Quarterly Spring 2009 1 Award-Winning Houses and Forward-Thinking Design J
    spring 2009 The Modern Log Home connecting to the outdoors with environmentally friendly structures The Hine Group satisfying clients through web accessibility Lloyd Construction blending sustainability with style J. HALL HOMES , INC. custom residential homebuilder has a reputation for american builders quarterly spring 2009 1 award-winning houses and forward-thinking design j. hall homes, inc. distinctive custom jeff hall, president and owner of j. you have to educate the customer that homebuilder sees Hall Homes, Inc. of Fredericksburg, VA, [building green] is going to cost less in future in green has always been a construction/design the long run.” practices pioneer of sorts. Growing up, he was the first in his neighborhood to build Thanks to builders like J. Hall Homes, by Ashley Morris two half-pipe skateboard ramps. To- a growing number of regional clients day, Hall is the first Fredericksburg-area are realizing the cost benefits of build- builder to successfully erect and certify ing greenly. Hall chooses the green blue- an Energy Star home. prints of Energy Star and EarthCraft, a program incepted in Atlanta in 1999, “Eighty percent of homes in the West are the same birth year of J. Hall Homes. Energy Star [homes],” says Hall. “In the “Compared to LEED, EarthCraft is easier East, it’s at two percent. But you see to work with,” says Hall. He hopes to be green everywhere—energy costs are up, fully committed to building EarthCraft values are down, and people are look- homes in the next three to five years. Above: The LeMay floor plan, ing to save money long term.
    [Show full text]
  • Furnishing & Interpretative Plan Haislip – Hall House
    Furnishing & Interpretative Plan Haislip – Hall House Brentsville Courthouse Historic Centre 12229 Bristow Road Bristow, VA 20136 Prince William County Department of Public Works – Historic Preservation Division 17674 Main Street Dumfries, VA 22026 Furnishing and Interpretative Plan for the Haislip-Hall House at Bristow, VA Brentsville Courthouse Historic Centre Historic Preservation Division Prince William County TABLE OF CONTENTS Administrative Information Page Mission Statement 1 Staff 1 Interpretive Objectives 1 Historical Information Time Period 2 History of Title/Occupancy 2 Historical Narrative Haislip-Hall Families 3-4 Prince William County in 1850 5-7 Architectural Description 8-9 Furnishing Plan First Floor, North “Kitchen” Room 10-13 First Floor, Closet 14 First Floor, Hall 14-15 Second Floor, Bed Chamber 15-16 Second Floor, Small Bed Chamber Room 16 Grounds Plan Garden 17 Animal Paddock 17 Hog Pen 17 Smoke House 18 Spring House 18 Appendixes 1. Interpretative/Tour Outline 20-21 2. House Layout 22 3. Ground Layout 23 4. Federal Census Information 24-33 5. Agricultural Census Information 34-37 6. Miscellaneous Government Documents 38 7. Haislip Personal Property Tax List, 1855-1861 39-46 8. Land and Deed Timeline 47-49 9. James Purcell’s Land and Will Inventory 50 10. Benson Lynn’s Land and Will Inventory 51 11. Joseph Johnson’s Land and Will Inventory 52 12. Theron Newman’s Land and Will Inventory 53 13. Family Life on the Frontier by George Caleb Bingham 54 14. Winding Up by William Sidney Mount 55 15. Kitchen in the Mount House by William Sidney Mount 56 16. The Sportman’s Last Visit by William Sideny Mount 57 17.
    [Show full text]
  • 2021 2022 Living on Campus Handbook
    2021 LIVING ON CAMPUS 2022 HANDBOOK Residence Halls, East Campus Apartments, West Campus Apartments, and Nicholson Gateway Apartments LIVING ON CAMPUS HANDBOOK 1 WELCOME TO CAMPUS From orientation to graduation, there is a home for you on campus. Welcome to the community! Close to 8,000 students live in on-campus communities that are intentionally designed to support your transition into and through college, your academic success, and holistic personal development. I hope you will get involved, influence your living environment, and truly experience the best of LSU. With students and staff from all corners of the globe, we are committed to creating an inclusive and respectful home for everyone in our communities. Whether it’s attending the entertaining community programs, having dialogue on tough topics, holding one another accountable to community standards, or learning through study groups, take advantage of all the services and support staff your community provides. This handbook presents important information you need to know about the services, policies, and procedures for residential communities at LSU. Familiarize yourself with the information in this handbook and contact a Residential Life staff member with any questions or concerns. Your live-in community staff members are a great resource. Look for your residence coordinator in their office in your building, at community programs, and the dining halls! Again, welcome and best wishes for a successful year! Geaux Tigers! Peter Trentacoste Executive Director, Residential Life TABLE OF CONTENTS Coronavirus Community Standards 2 Safety 23 Community Living 3 Services 26 Policies 12 Important Phone Numbers 29 Procedures 20 Appendix A: Housing Contract 31 Residence hall specific information is Apartment specific information is highlighted in gold.
    [Show full text]
  • FYRE Brochure 2020.Pdf
    GUIDE TO FIRST-YEAR LIVING www.nyu.edu/living-on 2020–2021 WHAT IS THE FIRST YEAR RESIDENTIAL EXPERIENCE? At NYU, we believe New York is more than just the city where you live. It is a vital partner in your educational experience. It demands you look closely at the critical issues facing you — not only in your academic work, but in the community and world around you. As a new student living in one of the residence halls, you will be part of the First Year Residential Experience (FYRE). FYRE provides opportunities to attend programs and activities designed to help you transition smoothly into your first year of college. Each hall has passionate faculty, professional, and student team members equipped with the knowledge and skills to help you make the most of your first year at NYU. The experiences provided in your residence hall will help you connect to new friends, NYU, and New York City. Each hall has a strong hall government for students so it’s easy to get involved, become a part of NYU’s best traditions, and gain experience as a student leader on campus. WHAT ARE THEMED ENGAGEMENT COMMUNITIES? Incoming students can take advantage of two types of themed engagement community options in their first year, each designed to enhance the NYU experience. These com- munities will enhance your classroom experiences and help you connect with other students, the city, and professors in a meaningful way. A key part of each community are incredible outings into NYC (at no additional cost!) led by NYU profes- sors that will feed and ignite your passions and interests.
    [Show full text]
  • Woodburning Appliances Instructional Brochure (PDF)
    Woodburning Appliance Ordinance Frequently Asked Questions Why did the City of Santa Rosa Control District or be a gas log If I have one of the old and non- pass a Woodburning Appliance fireplace. compliant models, how am I affected Ordinance? • Remodels: If a homeowner is by the ordinance? The City Council was concerned remodeling within 12 inches of an On June 1, 2004, it will be unlawful about the impact of wood smoke on older model freestanding wood to use or operate one of these its residents. The City Council stove or an older model fireplace wood stoves or inserts. You do not believed that there was a need to insert and the remodel work need to replace the appliance, but adopt an ordinance to lessen the exceeds $2,500, the homeowner you will not be able to use it. risk to human health and the envi- will be asked to remove the How do I determine if my wood stove ronment caused by woodburning appliance. This does not apply to or appliance is affected by the ordi- appliances. fireplaces without an insert or a nance? pellet stove. When does the ordinance go into Generally, if it was made before effect? If I have a traditional open hearth 1991, or has metal doors it does not The Council adopted the ordinance fireplace in my home, am I affected comply. You can also look on the on June 18, 2002 and it was effec- by this ordinance? back of your wood stove for the tive 30 days later. The immediate No, it excludes traditional open EPA certification label.
    [Show full text]
  • RESIDENCE HALLS | 2017 - 2018 BRUMBY- CASTLE HALL Women’S Residence
    RESIDENCE HALLS | 2017 - 2018 BRUMBY- CASTLE HALL women’s residence HALL INFORMATION features • 3-story suite style residence hall • Wireless internet • 4 computer labs within the hall for residents • Ethernet • Cable TV ROOM INFORMATION • Washer/Dryer • Elevator • Room furniture includes 2 beds (single/bunk), • Vending machines 2 built-in desks with chairs, 2 built-in chests • Window blinds and a waste can • The closet is a shelf/rod combination pricing • Multicolored carpet in rooms • Bathroom includes 2 sinks, cabinets and • $2,225.00 room cost per semester drawers, toilet, shower, several towel racks • $1,112.50 private room fee per semester and shelves above the toilet LAWLER-HARKINS HALL women’s residence HALL INFORMATION • 3-story suite style residence hall with first and second floor lobby areas • Common kitchen with a stove, refrigerator, sink and counter space ROOM INFORMATION • Room furniture includes 2 beds (single/bunk), 2 built-in desks with chairs, 2 built-in chests and a waste can. • There are two closets with a shelf at the top of each. • Tiled flooring. • Bathroom includes vanity with sink, drawers and cabinets, toilet, full sized shower/tub, 2 large medicine cabinets and towel racks. features • Wireless internet • Ethernet • Cable TV • Washer/Dryer • Vending machines • Window blinds • Surveillance cameras pricing • $2,200.00 room cost per semester • $1,100.00 private room fee per semester BLANSETT HALL men’s residence HALL INFORMATION features • 3-story suite residence hall with a spacious • Wireless internet first floor
    [Show full text]
  • Campus Features Potter Auditorium (Upper Level)  47 47
    Academic and Student Housing Administrative 44 27. Apartment Village R Facilities 28. The Lodge R 45 1. Shawnee Hall 29. Taylor Residence Center R Craig-Dorland Theatre 30. Agee Residence Center R (second floor) 31. Kerr Residence Hall R 2. Thurmond Hall Handicap Access 32. WMU Residence Center R Admissions 26 33. West University Apartments R 3. W.P. Wood Parking Designations 34. Devereaux West Apartments R 46 Science Building O R Residents of adjacent 35. Howard Residence Complex R 4. Art Building student housing only (See Student Housing list 36. Devereaux East Apartments R 5. Art Annex at right for permit colors) 37. Burns/Cobbs Apartments R 6. Science Annex C Commuter Student 7. Marriage and Family Therapy Center E Employees Sports Facilities 8. Ford Hall V Visitor 38. Bison Football Practice Field and Locker Room 9. Bailey Business Center O Open 39. Tennis Courts 10. Montgomery Hall 40. Sand Volleyball 11. Jane E. & Nick K. Stavros Hall 43 41. Hurt Memorial Track Complex and 12. Owens Hall Crain Family Stadium 13. Mabee Learning Center 42. Intramural Fields 14. Sarkeys Telecommunication Center 43. Soccer Complex 15. Geiger Center 44. Bison Field at Ford Park 16. Stubblefield Chapel 45. Lady Bison Softball Park 17. Aramark O 46. Baseball Practice Field 18. University Police Department 19. Raley Chapel Campus Features Potter Auditorium (upper level) 47 47. Disc Golf Course Yarborough Auditorium (lower level) R 48. Millennium Park 20. Noble Complex for Athletics 49. Virtus Bison Sculptures 27 21. Recreation and Wellness Center 48 R R 50. Quadrangle / Clock Tower 22. J.
    [Show full text]
  • House Redistricting Town Hall FAQ
    House Redistricting Town Hall FAQ 1. Will the meeting be livestreamed or recorded and how can I watch? Yes, redistricting town halls will be livestreamed when possible. The ability to livestream is dependent on the reliability of the internet access and technological capabilities of the host facility on the day the meeting takes place. House livestreams are accessible here, no signup required. This is the same link where the public can currently watch live proceedings of House committee meetings and floor sessions. When livestreaming is not possible or disrupted, a recording will be made available at the same link under the “recordings” page a few days after the meeting. At this time, we anticipate that livestreaming will be available at the Oklahoma City, Tulsa, Tahlequah, Lawton, Ardmore and Woodward meetings. 2. Will there be an opportunity for the questions and comments by the public? There will be a time set aside for Q&A and public comment following a brief presentation. A standing microphone will be placed at the center of the room for attendees to approach and ask questions. Alternatively, when a standing microphone is not available or practical, a staff member will bring a microphone to the person asking questions. 3. Do I need to register to attend? If so, how do I do that? No registration is required. Every meetings is open to anyone who would like to attend and intended to be an opportunity for the public and local stakeholders to learn more about redistricting, make suggestions and have their voices heard throughout the process. 4.
    [Show full text]
  • THE DENISON ARCHWAY” Or “THE ENGINEERING ARCH”
    “THE DENISON ARCHWAY” or “THE ENGINEERING ARCH” The famous “Engineering Arch” in the New Engineering Building (later called West Engineering and then West Hall) was the contribution of an engineering professor, Charles Denison. When he learned that there was a serious problem of how to design the building without interfering with the diagonal walk of the campus, he prepared a sketch showing the diagonal walk passing through an archway in the building. The New Engineering Building - 1903 The Arch was named “The Denison Archway” Later, known as the “Engineering Arch” Charles Simeon Denison Charles Simeon Denison’s nickname was ‘Little Lord Chesterfield,’ for he was the Beau Brummel of the University. His slightly curly hair matched the shine on his boots. His ties matched his socks. His wardrobe contained unnumbered suits of clothes and overcoats for all kinds of weather. The collars of some of his topcoats were of expensive fur. He had all kinds of haberdashery, including more than forty shirts. He did not have these laundered in Ann Arbor, but sent them each month to Chicago for ‘proper’ laundering.” (Mortimer Cooley, Scientific Blacksmith, p. 96) “He was a good man, and he came of a long line of good men. The family traces its lineage from Antenor, King of the Cimbri, of the Trojan nobility, born about 1239 B.C., down through Charlemagne and a royal line to Captain George Denison of Stonington, Connecticut, who came to America in 1631, and who achieved distinction for services rendered in Cromwell’s army and in our own Indian wars.” (The Michigan Technic, 5/1914) Charles Simeon Denison received a B.
    [Show full text]
  • Wall Erosion in 2D Hybrid Hall Thruster Simulation
    Wall Erosion in 2D Hall Thruster Simulations IEPC-2005-189 Presented at the 29th International Electric Propulsion Conference, Princeton University, October 31 – November 4, 2005 Emmanuelle Sommier*, Michelle K. Allis†, and Mark A. Cappelli¶ Stanford University, Stanford, CA, 94305 A 2D radial-axial hybrid PIC model has been developed in order to better understand the interactions that occur in Hall thrusters between the plasma and the channel walls. The thruster model geometry corresponds to the Stanford Hall Thruster and the computational domain extends from the anode, through the interior channel, and into the near field plume region. The discharge simulation was carried out for a discharge voltage of 200V and a discharge current of 2.5A. In order to assess thruster degradation due to sputtering, a model of the channel wall erosion process has been added to the simulation as the result of the interaction with the walls of energetic ions and energetic neutrals. The significance of ion- neutral collisions and sheath effects in the erosion process has been studied. These simulations are then used as the basis for computational models that adjust the geometry of the thruster and predict the erosion of the insulator channel walls due to continued sputtering. It was observed that, as the wall is eroded, the erosion rate decreases with time, and that the erosion of the wall reaches 2 to 3 mm after 2000 hours. Nomenclature Br = radial magnetic field e = electron charge E = electric field E* = crossover energy Ee = energy of a primary electron
    [Show full text]