天津大学学报
天津大學學報
천진대학학보
JOURNAL OF TIANJIN UNIVERSITY SCIENCE AND TECHNOLOGY
2013年
8期
719-725
,共7页
聂建华%沈建国%李山生%沈永进
聶建華%瀋建國%李山生%瀋永進
섭건화%침건국%리산생%침영진
超声波%探头%电缆%分布参数模型%长度
超聲波%探頭%電纜%分佈參數模型%長度
초성파%탐두%전람%분포삼수모형%장도
ultrasound%transducer%cable%distributed parameter model%length
超声波采油和管道清洗施工均需要特殊的长距离电缆。为使激励源产生的高频电能量能够有效地经电缆长距离传输到探头上,必须首先解决电缆与探头间的匹配问题。利用探头的集总参数和电缆的分布参数模型研究了电缆输入阻抗随频率和电缆长度的变化规律。在探头的谐振频率处,电缆的特征阻抗与探头的动态阻抗相等时,电缆与探头是最佳匹配;不相等时,电缆的输入阻抗或导纳均随频率变化,具有一系列的峰值。导纳的峰值对应1/2波长,阻抗的峰值对应1/4波长。用4,294,A 阻抗分析仪测量到了这些峰值,频率越高其峰值越小。电缆接探头后,这些峰值向低频移动。考虑到大功率超声电源内阻较小,电缆与探头匹配时,应使电缆长度为1/2波长附近,导纳的极大值位于探头的谐振频率处。并联匹配电感用于抵消探头导纳的虚部。
超聲波採油和管道清洗施工均需要特殊的長距離電纜。為使激勵源產生的高頻電能量能夠有效地經電纜長距離傳輸到探頭上,必鬚首先解決電纜與探頭間的匹配問題。利用探頭的集總參數和電纜的分佈參數模型研究瞭電纜輸入阻抗隨頻率和電纜長度的變化規律。在探頭的諧振頻率處,電纜的特徵阻抗與探頭的動態阻抗相等時,電纜與探頭是最佳匹配;不相等時,電纜的輸入阻抗或導納均隨頻率變化,具有一繫列的峰值。導納的峰值對應1/2波長,阻抗的峰值對應1/4波長。用4,294,A 阻抗分析儀測量到瞭這些峰值,頻率越高其峰值越小。電纜接探頭後,這些峰值嚮低頻移動。攷慮到大功率超聲電源內阻較小,電纜與探頭匹配時,應使電纜長度為1/2波長附近,導納的極大值位于探頭的諧振頻率處。併聯匹配電感用于牴消探頭導納的虛部。
초성파채유화관도청세시공균수요특수적장거리전람。위사격려원산생적고빈전능량능구유효지경전람장거리전수도탐두상,필수수선해결전람여탐두간적필배문제。이용탐두적집총삼수화전람적분포삼수모형연구료전람수입조항수빈솔화전람장도적변화규률。재탐두적해진빈솔처,전람적특정조항여탐두적동태조항상등시,전람여탐두시최가필배;불상등시,전람적수입조항혹도납균수빈솔변화,구유일계렬적봉치。도납적봉치대응1/2파장,조항적봉치대응1/4파장。용4,294,A 조항분석의측량도료저사봉치,빈솔월고기봉치월소。전람접탐두후,저사봉치향저빈이동。고필도대공솔초성전원내조교소,전람여탐두필배시,응사전람장도위1/2파장부근,도납적겁대치위우탐두적해진빈솔처。병련필배전감용우저소탐두도납적허부。
Special ultrasound cable is designed to meet the demand of ultrasonic oil extraction and pipeline cleaning for the propagation of high-frequency ultrasonic power over a great distance to transducer located underground. Cable input impedance versus frequency and length curve was studied by making use of the transducer lumped-parameter model and the cable distributed-parameter model. As a conclusion,when the characteristic impedance of the cable and the impedance of the transducer are equal at transducer resonant frequency,they achieve the best match;if they are not equal,the impedance or admittance of the cable varies with frequency,and both real and imaginary parts have a series of peaks. Admittance peak corresponds to half wave length,and impedance peak to quarter wave length. 4,294,A impedance analyzer was used to measure these peaks,and it was found that the higher the frequency,the smaller the peak value. After the cable and the transducer were connected,these peaks were found to move to the low-frequency region. Considering the small inner resistance of ultrasound power source,the cable length should be the half of wave length,and the maximum admittance of the cable should be within the resonant frequency of the transducer for an optimal design. Matching inductor is used to offset the imaginary part of transducer admittance in practical application.