本發明(ming)涉(she)及吸(xi)聲結構(gou)(gou),尤其涉(she)及一種多(duo)層突(tu)變(bian)截面穿孔板低(di)頻吸(xi)聲結構(gou)(gou)及其制造方法。
背景技術:
1、吸(xi)(xi)聲(sheng)材料(liao)(liao)種類比(bi)較多(duo),按其材料(liao)(liao)結(jie)構狀況可分(fen)(fen)為兩大類,分(fen)(fen)別(bie)為多(duo)孔吸(xi)(xi)聲(sheng)材料(liao)(liao)和共振(zhen)吸(xi)(xi)聲(sheng)結(jie)構,常用的多(duo)孔吸(xi)(xi)聲(sheng)材料(liao)(liao)對(dui)中高頻吸(xi)(xi)聲(sheng)效(xiao)果(guo)比(bi)較好,對(dui)低頻的吸(xi)(xi)聲(sheng)性能比(bi)較差。
技術實現思路
1、本申請實(shi)施例通(tong)(tong)過(guo)提(ti)供一種多(duo)層突變截面(mian)穿(chuan)孔(kong)板低頻吸聲(sheng)結(jie)構及其制造方(fang)法,解決(jue)了現有技(ji)術中多(duo)孔(kong)吸聲(sheng)材料對低頻噪(zao)聲(sheng)的(de)(de)吸聲(sheng)性能差(cha)的(de)(de)問題,通(tong)(tong)過(guo)多(duo)層突變截面(mian)穿(chuan)孔(kong)板結(jie)構的(de)(de)組合,提(ti)高了吸聲(sheng)裝置對低頻噪(zao)聲(sheng)的(de)(de)吸收和(he)消耗(hao)的(de)(de)能力。
2、本申(shen)請(qing)實(shi)施例提供了(le)一種多層突變(bian)(bian)截面穿孔(kong)板(ban)低頻吸聲(sheng)結構,包括突變(bian)(bian)截面穿孔(kong)板(ban)、剛性壁、變(bian)(bian)截面穿孔(kong)裝置;
3、所(suo)述突(tu)變(bian)截面穿孔板為正(zheng)方(fang)體形(xing)結構;
4、所述突變截(jie)(jie)面穿(chuan)孔板(ban)下方活動連(lian)接有(you)剛性壁(bi),剛性壁(bi)與(yu)突變截(jie)(jie)面穿(chuan)孔板(ban)形狀相同;
5、所(suo)述突變(bian)截(jie)面穿孔(kong)(kong)板開設若干(gan)通(tong)孔(kong)(kong),每個通(tong)孔(kong)(kong)均(jun)固定連接(jie)一個變(bian)截(jie)面穿孔(kong)(kong)裝置;
6、每個(ge)所述變截面穿孔裝置均包(bao)括小(xiao)(xiao)孔徑(jing)穿孔板、大孔徑(jing)穿孔板、小(xiao)(xiao)穿孔、大穿孔;
7、所述大(da)孔(kong)(kong)徑穿(chuan)孔(kong)(kong)板為(wei)圓柱體形,突變(bian)截(jie)面穿(chuan)孔(kong)(kong)板開(kai)設(she)的通孔(kong)(kong)均固(gu)定連接一個大(da)孔(kong)(kong)徑穿(chuan)孔(kong)(kong)板,大(da)孔(kong)(kong)徑穿(chuan)孔(kong)(kong)板貫穿(chuan)開(kai)設(she)大(da)穿(chuan)孔(kong)(kong);
8、所述(shu)大孔徑(jing)(jing)穿(chuan)孔板遠離剛(gang)性壁的面固定連接小孔徑(jing)(jing)穿(chuan)孔板,小孔徑(jing)(jing)穿(chuan)孔板同軸(zhou)貫穿(chuan)開(kai)設小穿(chuan)孔;
9、每個所述變截面穿(chuan)孔裝置(zhi)上(shang)的(de)小穿(chuan)孔和大穿(chuan)孔相互連(lian)通。
10、進一(yi)步的(de)(de),低頻吸(xi)聲結(jie)構可由(you)多(duo)層(ceng)所述突變截面(mian)穿孔板拼接(jie)組成,通過控制突變截面(mian)穿孔板的(de)(de)層(ceng)數達到改變結(jie)構共振頻率目的(de)(de),吸(xi)收不同頻率的(de)(de)噪(zao)聲。
11、進一(yi)步的(de),所述突變截面穿孔(kong)板(ban)與剛性壁之間形成空腔。
12、進一步的(de),在兩層(ceng)突變截面穿(chuan)(chuan)孔(kong)板(ban)拼(pin)接的(de)低頻(pin)吸聲結構中,小(xiao)穿(chuan)(chuan)孔(kong)的(de)體(ti)積為小(xiao)孔(kong)徑(jing)穿(chuan)(chuan)孔(kong)板(ban)體(ti)積的(de)0.27%,小(xiao)孔(kong)徑(jing)穿(chuan)(chuan)孔(kong)板(ban)的(de)板(ban)厚(hou)為1mm,小(xiao)穿(chuan)(chuan)孔(kong)的(de)孔(kong)徑(jing)為1.5mm。
13、進一步(bu)的(de)(de),在兩層突變截面(mian)穿孔板拼接的(de)(de)低頻吸聲(sheng)結(jie)構中,大穿孔的(de)(de)體(ti)積為大孔徑(jing)(jing)穿孔板體(ti)積的(de)(de)0.27%,大孔徑(jing)(jing)穿孔板的(de)(de)板厚(hou)為1mm,大穿孔的(de)(de)孔徑(jing)(jing)為4mm,突變截面(mian)穿孔板層數為兩層時,空腔(qiang)的(de)(de)厚(hou)度設為39mm。
14、進一(yi)步的(de),在三層(ceng)突變(bian)截面穿(chuan)孔(kong)(kong)板(ban)拼接成的(de)低(di)頻吸(xi)聲結構中,小穿(chuan)孔(kong)(kong)的(de)體積為小孔(kong)(kong)徑(jing)穿(chuan)孔(kong)(kong)板(ban)體積的(de)?0.25%,小孔(kong)(kong)徑(jing)穿(chuan)孔(kong)(kong)板(ban)的(de)板(ban)厚(hou)為1mm,小穿(chuan)孔(kong)(kong)的(de)孔(kong)(kong)徑(jing)為1.5mm。
15、進一步的(de)(de),在(zai)三層(ceng)(ceng)突變(bian)截面(mian)穿孔(kong)(kong)板(ban)拼(pin)接成的(de)(de)低(di)頻吸聲結構中,大(da)穿孔(kong)(kong)的(de)(de)體積(ji)為(wei)大(da)孔(kong)(kong)徑穿孔(kong)(kong)板(ban)體積(ji)的(de)(de)0.27%,大(da)孔(kong)(kong)徑穿孔(kong)(kong)板(ban)的(de)(de)板(ban)厚(hou)為(wei)1mm,大(da)穿孔(kong)(kong)的(de)(de)孔(kong)(kong)徑為(wei)4mm,突變(bian)截面(mian)穿孔(kong)(kong)板(ban)的(de)(de)層(ceng)(ceng)數為(wei)三層(ceng)(ceng)時,空腔的(de)(de)厚(hou)度設(she)為(wei)25mm。
16、進一(yi)步的,所述(shu)變截面穿孔裝置還(huan)包括(kuo)喇叭口(kou);
17、每個所(suo)述大孔徑(jing)穿(chuan)孔板接近剛性(xing)壁的面均開(kai)設一(yi)個開(kai)口朝下(xia)的喇叭口;
18、每(mei)個所述變截(jie)面(mian)穿(chuan)孔裝置中小穿(chuan)孔和(he)大穿(chuan)孔相互(hu)連通構成(cheng)螺紋狀流(liu)道;
19、所述喇叭口與(yu)小穿孔和大穿孔相互連通構成螺(luo)紋狀流道相互連通。
20、進一步的,如圖(tu)6、圖(tu)7所(suo)示,多層(ceng)突(tu)變(bian)截面穿(chuan)孔板(ban)低頻吸聲(sheng)結構還包括(kuo)變(bian)截面穿(chuan)孔裝(zhuang)置(zhi)組;
21、每個(ge)所述變截面穿(chuan)(chuan)孔(kong)(kong)裝(zhuang)置內(nei)均包括兩(liang)個(ge)小(xiao)穿(chuan)(chuan)孔(kong)(kong)和大穿(chuan)(chuan)孔(kong)(kong)構成(cheng)的(de)螺紋(wen)狀流(liu)道(dao),兩(liang)組小(xiao)穿(chuan)(chuan)孔(kong)(kong)和大穿(chuan)(chuan)孔(kong)(kong)構成(cheng)的(de)流(liu)道(dao)螺紋(wen)纏繞(rao)且與喇(la)叭(ba)口連(lian)通;
22、兩層突變(bian)(bian)截(jie)面(mian)(mian)穿孔(kong)(kong)板拼(pin)接的低頻吸聲結構中,接近剛性壁的突變(bian)(bian)截(jie)面(mian)(mian)穿孔(kong)(kong)板固定連接的多個(ge)(ge)變(bian)(bian)截(jie)面(mian)(mian)穿孔(kong)(kong)裝(zhuang)置(zhi)組(zu)分為若干組(zu),每個(ge)(ge)變(bian)(bian)截(jie)面(mian)(mian)穿孔(kong)(kong)裝(zhuang)置(zhi)組(zu)由多個(ge)(ge)變(bian)(bian)截(jie)面(mian)(mian)穿孔(kong)(kong)裝(zhuang)置(zhi)構成,每個(ge)(ge)變(bian)(bian)截(jie)面(mian)(mian)穿孔(kong)(kong)裝(zhuang)置(zhi)組(zu)內的變(bian)(bian)截(jie)面(mian)(mian)穿孔(kong)(kong)裝(zhuang)置(zhi)排布方式為十字(zi)形;
23、兩(liang)層(ceng)突變截面(mian)穿(chuan)孔(kong)(kong)板(ban)拼接的低頻吸(xi)聲結構中(zhong),遠離剛性壁的突變截面(mian)穿(chuan)孔(kong)(kong)板(ban)開設(she)的每個喇叭口均與下層(ceng)突變截面(mian)穿(chuan)孔(kong)(kong)板(ban)中(zhong)的一(yi)組(zu)變截面(mian)穿(chuan)孔(kong)(kong)裝置(zhi)中(zhong)心點對應。
24、本申(shen)請還公布了一種(zhong)多(duo)層(ceng)突變截面穿孔板低頻吸聲(sheng)結構的制造方法(fa),包(bao)括如(ru)下步驟:
25、s1、測試驗(yan)證:根據微穿(chuan)孔(kong)板理論(lun)、傳(chuan)遞矩陣方法(fa)以及聲電類比原理,通(tong)過計(ji)算機模擬(ni)驗(yan)證穿(chuan)孔(kong)截(jie)面及突變截(jie)面穿(chuan)孔(kong)板的層(ceng)數的改變對于吸(xi)(xi)聲結構的吸(xi)(xi)聲效果的影響;
26、具(ju)體的(de),其聲學邊界的(de)連續性,兩層(ceng)、三層(ceng)和層(ceng)突(tu)變截面穿孔板結構的(de)系統傳遞矩陣表(biao)示為:
27、
28、其中(zhong)為層突變(bian)截(jie)面穿(chuan)孔板(ban)的層數,對(dui)于多層突變(bian)截(jie)面穿(chuan)孔板(ban)大小孔徑穿(chuan)孔板(ban),其傳遞矩陣為:
29、
30、突變截面(mian)穿(chuan)孔板(ban)大小孔徑穿(chuan)孔板(ban)的聲(sheng)阻(zu)抗表示為:
31、
32、其中(zhong)表示(shi)pp1和pp2的穿孔常數,定義為管(guan)內半徑與孔內粘性(xing)邊界層厚度(du)的比值,;表示(shi)空氣(qi)的動力黏(nian)度(du)系數,1.84×10-5;為空氣(qi)密度(du),1.21;、分別(bie)表示(shi)0階、1階bessel函(han)數。空腔單元矩陣表示(shi)為:
33、
34、其中為空(kong)氣(qi)域波數,;為第層空(kong)腔(qiang)厚度;表示(shi)(shi)空(kong)氣(qi)密度和聲速,傳遞矩(ju)(ju)陣描述多輸(shu)入多輸(shu)出(chu)線性系統(tong),采(cai)用矩(ju)(ju)陣形(xing)式表示(shi)(shi)為:
35、
36、由于剛性(xing)壁(bi)上粒子速度為零(ling)(=0),在聲(sheng)波垂直入(ru)射(she)下,以兩層(ceng)突(tu)變截面(mian)(mian)穿(chuan)孔板結構為例,其表面(mian)(mian)聲(sheng)阻抗為表面(mian)(mian)入(ru)射(she)聲(sheng)壓與聲(sheng)速的比值(zhi):
37、
38、兩層(ceng)突變截(jie)面穿孔板相對于空氣(qi)的(de)特性(xing)阻抗(kang),其相對聲阻抗(kang)為。聲波垂直入射(she)時的(de)吸聲系數(shu)為:
39、;
40、s2、設(she)計(ji):通過檢測驗證的(de)結(jie)果,設(she)計(ji)一(yi)種多層突變截面(mian)穿(chuan)孔(kong)板(ban)吸(xi)(xi)聲(sheng)(sheng)結(jie)構,可(ke)以(yi)確保設(she)計(ji)的(de)多層突變截面(mian)穿(chuan)孔(kong)板(ban)吸(xi)(xi)聲(sheng)(sheng)結(jie)構具有針對性(xing)的(de)吸(xi)(xi)聲(sheng)(sheng)性(xing)能,滿足不同頻率范圍的(de)噪聲(sheng)(sheng);
41、s3、制造(zao):基于上述吸(xi)(xi)(xi)(xi)聲(sheng)系數隨吸(xi)(xi)(xi)(xi)聲(sheng)結構(gou)表面(mian)(mian)聲(sheng)阻抗(kang)(kang)的(de)(de)變化規律,低(di)頻(pin)吸(xi)(xi)(xi)(xi)聲(sheng)結構(gou)采用多層(ceng)突變截面(mian)(mian)穿孔板(ban),通(tong)過改變突變截面(mian)(mian)穿孔板(ban)的(de)(de)層(ceng)數、孔隙率(lv)、小(xiao)穿孔孔徑、大穿孔孔徑、空腔厚度、達到改變吸(xi)(xi)(xi)(xi)聲(sheng)結構(gou)的(de)(de)聲(sheng)阻抗(kang)(kang)率(lv)的(de)(de)目的(de)(de),從而實(shi)現(xian)對不(bu)同低(di)頻(pin)、中低(di)頻(pin)噪(zao)聲(sheng)的(de)(de)吸(xi)(xi)(xi)(xi)收(shou),提高整體(ti)吸(xi)(xi)(xi)(xi)聲(sheng)效(xiao)果(guo)。
42、本申(shen)請實施例中提供的(de)一個或多個技術方案,至少具有如下技術效(xiao)果(guo)或優點(dian):
43、其一,聲音通過多(duo)層突(tu)變截(jie)面(mian)穿(chuan)孔(kong)(kong)板(ban)(ban)時(shi),突(tu)變截(jie)面(mian)穿(chuan)孔(kong)(kong)板(ban)(ban)上的(de)若干小穿(chuan)孔(kong)(kong)和大(da)穿(chuan)孔(kong)(kong)構(gou)成的(de)通道會對低頻噪聲進(jin)行吸收并振(zhen)動,使低頻噪音和兩層突(tu)變截(jie)面(mian)穿(chuan)孔(kong)(kong)板(ban)(ban)產生共振(zhen),進(jin)而實現(xian)吸收消(xiao)耗不同頻率(lv)的(de)噪聲。
44、其二,將(jiang)小(xiao)穿(chuan)孔(kong)(kong)和大穿(chuan)孔(kong)(kong)構(gou)成(cheng)的(de)(de)流道(dao)整體形狀改為螺紋狀,使噪(zao)音穿(chuan)過變(bian)(bian)截(jie)面(mian)(mian)穿(chuan)孔(kong)(kong)裝(zhuang)置(zhi)的(de)(de)路徑變(bian)(bian)長,從而(er)消耗更多(duo)的(de)(de)聲能,噪(zao)音穿(chuan)過小(xiao)穿(chuan)孔(kong)(kong)和大穿(chuan)孔(kong)(kong)構(gou)成(cheng)的(de)(de)流道(dao)進(jin)(jin)入到喇叭(ba)口(kou)(kou)后,會(hui)順(shun)著(zhu)喇叭(ba)口(kou)(kou)的(de)(de)內(nei)壁(bi)逐漸擴張,進(jin)(jin)入到下(xia)一層突變(bian)(bian)截(jie)面(mian)(mian)穿(chuan)孔(kong)(kong)板表面(mian)(mian)的(de)(de)更多(duo)變(bian)(bian)截(jie)面(mian)(mian)穿(chuan)孔(kong)(kong)裝(zhuang)置(zhi)中,進(jin)(jin)而(er)使突變(bian)(bian)截(jie)面(mian)(mian)穿(chuan)孔(kong)(kong)板的(de)(de)吸聲效(xiao)果(guo)進(jin)(jin)一步的(de)(de)提(ti)高。
45、其三,每個所述變(bian)(bian)截面(mian)(mian)穿(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)孔(kong)裝(zhuang)置內均包括(kuo)兩(liang)個小穿(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)孔(kong)和(he)大穿(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)孔(kong)構成的螺(luo)(luo)紋(wen)狀(zhuang)流道(dao),兩(liang)組小穿(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)孔(kong)和(he)大穿(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)孔(kong)構成的流道(dao)螺(luo)(luo)紋(wen)纏(chan)繞(rao),聲音在穿(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)過(guo)兩(liang)個螺(luo)(luo)旋纏(chan)繞(rao)的流道(dao)時會相(xiang)互(hu)影響振動,遠離剛性(xing)壁(bi)的突變(bian)(bian)截面(mian)(mian)穿(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)孔(kong)板開設的每個喇叭口均與接近(jin)剛性(xing)壁(bi)的突變(bian)(bian)截面(mian)(mian)穿(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)孔(kong)板中(zhong)的一(yi)組變(bian)(bian)截面(mian)(mian)穿(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)孔(kong)裝(zhuang)置組中(zhong)心對應(ying),從(cong)而使上層(ceng)突變(bian)(bian)截面(mian)(mian)穿(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)孔(kong)板上的單個喇叭口傳出的噪音可以被下層(ceng)的變(bian)(bian)截面(mian)(mian)穿(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)孔(kong)裝(zhuang)置組中(zhong)的多個突變(bian)(bian)截面(mian)(mian)穿(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)孔(kong)板吸(xi)(xi)收消(xiao)耗(hao),進一(yi)步提高了低頻(pin)吸(xi)(xi)聲結構的工作效率(lv)。
1.一(yi)種多層突變(bian)截(jie)(jie)面(mian)(mian)穿(chuan)孔板低頻吸聲結構,包(bao)括突變(bian)截(jie)(jie)面(mian)(mian)穿(chuan)孔板(100)、剛性壁(200)、變(bian)截(jie)(jie)面(mian)(mian)穿(chuan)孔裝置(300);
2.如(ru)權利要(yao)求1所述(shu)的一(yi)種多層突(tu)變截面(mian)穿孔板低(di)頻吸聲結構,其特(te)征(zheng)在于(yu),所述(shu)變截面(mian)穿孔裝置(300)還包括喇叭口(350);
3.如權利(li)要(yao)求1所(suo)述(shu)的一種多層突變截面穿孔(kong)板(ban)低頻吸聲(sheng)結構,其特征在于,低頻吸聲(sheng)結構可由(you)多層所(suo)述(shu)突變截面穿孔(kong)板(ban)(100)拼(pin)接組成。
4.如權利要求3所(suo)述的(de)一種多層突變截(jie)面穿孔(kong)(kong)板低頻吸(xi)聲結構(gou)(gou),其特征在于,每個所(suo)述變截(jie)面穿孔(kong)(kong)裝置(300)內均(jun)包括兩個小穿孔(kong)(kong)(330)和大穿孔(kong)(kong)(340)構(gou)(gou)成的(de)螺(luo)紋(wen)狀流道,兩組(zu)小穿孔(kong)(kong)(330)和大穿孔(kong)(kong)(340)構(gou)(gou)成的(de)流道螺(luo)紋(wen)纏(chan)繞且(qie)與喇叭口(350)連通(tong);
5.如權(quan)利要求1所述的一種(zhong)多層突(tu)變截(jie)面穿孔(kong)板(ban)低頻吸聲結構,其(qi)特征在于(yu),所述突(tu)變截(jie)面穿孔(kong)板(ban)(100)與剛性壁(200)之(zhi)間形成(cheng)空腔(400)。
6.如權利(li)要求1所述的(de)(de)一種多層突變(bian)截面穿(chuan)孔(kong)板低頻吸聲(sheng)(sheng)結構,其(qi)特征在于(yu),在兩層突變(bian)截面穿(chuan)孔(kong)板(100)拼接的(de)(de)低頻吸聲(sheng)(sheng)結構中,小(xiao)穿(chuan)孔(kong)(330)的(de)(de)體積(ji)為小(xiao)孔(kong)徑(jing)穿(chuan)孔(kong)板(310)體積(ji)的(de)(de)0.27%,小(xiao)孔(kong)徑(jing)穿(chuan)孔(kong)板(310)的(de)(de)板厚為1mm,小(xiao)穿(chuan)孔(kong)(330)的(de)(de)孔(kong)徑(jing)為1.5mm。
7.如權利要求(qiu)1所述的(de)(de)(de)(de)(de)一種多層突(tu)變(bian)(bian)截面穿(chuan)(chuan)(chuan)孔(kong)(kong)(kong)板低(di)頻吸聲結構,其特(te)征(zheng)在(zai)于,在(zai)兩層突(tu)變(bian)(bian)截面穿(chuan)(chuan)(chuan)孔(kong)(kong)(kong)板(100)拼(pin)接的(de)(de)(de)(de)(de)低(di)頻吸聲結構中,大(da)穿(chuan)(chuan)(chuan)孔(kong)(kong)(kong)(340)的(de)(de)(de)(de)(de)體積為(wei)大(da)孔(kong)(kong)(kong)徑穿(chuan)(chuan)(chuan)孔(kong)(kong)(kong)板(320)體積的(de)(de)(de)(de)(de)0.27%,大(da)孔(kong)(kong)(kong)徑穿(chuan)(chuan)(chuan)孔(kong)(kong)(kong)板(320)的(de)(de)(de)(de)(de)板厚(hou)為(wei)1mm,大(da)穿(chuan)(chuan)(chuan)孔(kong)(kong)(kong)(340)的(de)(de)(de)(de)(de)孔(kong)(kong)(kong)徑為(wei)4mm,突(tu)變(bian)(bian)截面穿(chuan)(chuan)(chuan)孔(kong)(kong)(kong)板(100)層數為(wei)兩層時,空腔(400)的(de)(de)(de)(de)(de)厚(hou)度設(she)為(wei)39mm。
8.如(ru)權利(li)要求1所述的(de)一(yi)種(zhong)多層突變截(jie)面(mian)穿(chuan)(chuan)孔(kong)(kong)(kong)板(ban)低頻吸(xi)聲結構,其(qi)特征在(zai)于,在(zai)三層突變截(jie)面(mian)穿(chuan)(chuan)孔(kong)(kong)(kong)板(ban)(100)拼接成(cheng)的(de)低頻吸(xi)聲結構中,小穿(chuan)(chuan)孔(kong)(kong)(kong)(330)的(de)體(ti)(ti)積(ji)為小孔(kong)(kong)(kong)徑穿(chuan)(chuan)孔(kong)(kong)(kong)板(ban)(310)體(ti)(ti)積(ji)的(de)0.25%,小孔(kong)(kong)(kong)徑穿(chuan)(chuan)孔(kong)(kong)(kong)板(ban)(310)的(de)板(ban)厚為1mm,小穿(chuan)(chuan)孔(kong)(kong)(kong)(330)的(de)孔(kong)(kong)(kong)徑為1.5mm。
9.如(ru)權(quan)利要求(qiu)1所述的(de)一種多層(ceng)突變截(jie)面穿(chuan)孔(kong)板低(di)頻吸聲(sheng)結(jie)構,其(qi)特征在于(yu),在三(san)層(ceng)突變截(jie)面穿(chuan)孔(kong)板(100)拼接成的(de)低(di)頻吸聲(sheng)結(jie)構中,大(da)穿(chuan)孔(kong)(340)的(de)體積為大(da)孔(kong)徑穿(chuan)孔(kong)板(320)體積的(de)0.27%,大(da)孔(kong)徑穿(chuan)孔(kong)板(320)的(de)板厚為1mm,大(da)穿(chuan)孔(kong)(340)的(de)孔(kong)徑為4mm,突變截(jie)面穿(chuan)孔(kong)板(100)的(de)層(ceng)數(shu)為三(san)層(ceng)時(shi),空腔(400)的(de)厚度為25mm。
10.如權(quan)利要(yao)求1-9任意(yi)一(yi)項權(quan)利要(yao)求所述的(de)一(yi)種多層突變(bian)截(jie)面穿孔板(ban)低頻吸聲結構的(de)制造方法(fa),其特(te)征在于,包括如下步驟(zou);
11.其(qi)中為層突(tu)變截面(mian)(mian)穿孔(kong)(kong)(kong)板(ban)(100)的(de)層數,對于(yu)多(duo)層突(tu)變截面(mian)(mian)穿孔(kong)(kong)(kong)板(ban)(100)大小孔(kong)(kong)(kong)徑穿孔(kong)(kong)(kong)板(ban),其(qi)傳(chuan)遞矩陣為:
12.突變截面穿孔(kong)(kong)板(100)大小孔(kong)(kong)徑穿孔(kong)(kong)板的聲阻(zu)抗(kang)表示(shi)為:
13.其(qi)中表(biao)(biao)示pp1和pp2的(de)穿(chuan)孔常數(shu)(shu)(shu),定(ding)義(yi)為管內(nei)半徑與(yu)孔內(nei)粘(zhan)性邊界層厚度(du)的(de)比值,;表(biao)(biao)示空氣(qi)的(de)動力黏度(du)系(xi)數(shu)(shu)(shu),1.84×10-5;為空氣(qi)密度(du),1.21;、分(fen)別表(biao)(biao)示0階(jie)、1階(jie)bessel函數(shu)(shu)(shu);
14.其中為(wei)空氣(qi)域波數(shu),;為(wei)第(di)層(ceng)空腔厚度;表(biao)(biao)示空氣(qi)密度和聲速,傳遞矩(ju)陣描述多輸(shu)入多輸(shu)出線性系統,采(cai)用矩(ju)陣形式表(biao)(biao)示為(wei):
15.由于剛(gang)性壁(200)上粒(li)子速(su)度為零(=0),在聲(sheng)波垂直入射下(xia),以兩層突變(bian)截面穿孔板(100)結構為例(li),其表面聲(sheng)阻抗為表面入射聲(sheng)壓(ya)與聲(sheng)速(su)的比值:
16.兩層(ceng)突變截面(mian)穿孔板(100)相(xiang)對于空氣的特(te)性(xing)阻(zu)抗,其相(xiang)對聲(sheng)阻(zu)抗為;