粉末冶金材料科学与工程
粉末冶金材料科學與工程
분말야금재료과학여공정
POWDER METALLURGY MATERIALS SCIENCE AND ENGINEERING
2015年
3期
470-477
,共8页
李小川%陈明军%刘颀%王启立%罗会清%柴伟豪
李小川%陳明軍%劉頎%王啟立%囉會清%柴偉豪
리소천%진명군%류기%왕계립%라회청%시위호
通风输送%粉尘沉积%水平直管%90°弯管%三通管
通風輸送%粉塵沉積%水平直管%90°彎管%三通管
통풍수송%분진침적%수평직관%90°만관%삼통관
ventilation conveyer process%dust deposition%horizontal straight pipe%90° bend pipe%Tbend pipe
粉尘沉积是通风输送过程的常见现象,严重时常堵塞管路,本文以实验研究为手段,探讨高浓度粉尘在通风输送过程的沉积特性。得出水平直管内粉尘的沉积受风速主导,较大风速湍流强度大,边界层厚度薄,有利于外流区粉尘的悬浮和边界层内粉尘的再次悬浮;水平90°弯管内粉尘沉积具有区域性,弯头上游以有序沉积为主,弯头下游由于气流边界层分离产生了漩涡区使沉积量急剧减少,弯头外侧由于流动偏移对壁面的冲刷使粉尘沉积几率降低,而弯管内侧由于边界层分离和部分粉尘随气流的偏移使沉积量最小;水平三通管内粉尘沉积主要受支管角度与流速影响。通风输送高浓度粉尘的合适取值为:水平直管和90°弯管风速应不低于17 m/s,水平三通角度30°~45°,支管风速不超过主管。
粉塵沉積是通風輸送過程的常見現象,嚴重時常堵塞管路,本文以實驗研究為手段,探討高濃度粉塵在通風輸送過程的沉積特性。得齣水平直管內粉塵的沉積受風速主導,較大風速湍流彊度大,邊界層厚度薄,有利于外流區粉塵的懸浮和邊界層內粉塵的再次懸浮;水平90°彎管內粉塵沉積具有區域性,彎頭上遊以有序沉積為主,彎頭下遊由于氣流邊界層分離產生瞭漩渦區使沉積量急劇減少,彎頭外側由于流動偏移對壁麵的遲刷使粉塵沉積幾率降低,而彎管內側由于邊界層分離和部分粉塵隨氣流的偏移使沉積量最小;水平三通管內粉塵沉積主要受支管角度與流速影響。通風輸送高濃度粉塵的閤適取值為:水平直管和90°彎管風速應不低于17 m/s,水平三通角度30°~45°,支管風速不超過主管。
분진침적시통풍수송과정적상견현상,엄중시상도새관로,본문이실험연구위수단,탐토고농도분진재통풍수송과정적침적특성。득출수평직관내분진적침적수풍속주도,교대풍속단류강도대,변계층후도박,유리우외류구분진적현부화변계층내분진적재차현부;수평90°만관내분진침적구유구역성,만두상유이유서침적위주,만두하유유우기류변계층분리산생료선와구사침적량급극감소,만두외측유우류동편이대벽면적충쇄사분진침적궤솔강저,이만관내측유우변계층분리화부분분진수기류적편이사침적량최소;수평삼통관내분진침적주요수지관각도여류속영향。통풍수송고농도분진적합괄취치위:수평직관화90°만관풍속응불저우17 m/s,수평삼통각도30°~45°,지관풍속불초과주관。
Dust deposition, which blocks the pipeline in sometimes, is a very common phenomenon in ventilation conveyer process. The deposition characteristic of high concentration dust in ventilation conveyer process was discussed and studied in the present paper. The primary conclusions are as follows: In horizontal straight pipe the dust deposition are leading by airflow velocity. The greater airflow velocity the greater turbulence intensity and the thinner boundary layer thickness are. It contributes to the dust suspension in the external flow area and the secondary suspension of dust in the boundary layer. It has the regional characteristics of the dust deposition in 90° bend. The orderly deposition of dust is the mainly action in upstream of bent. In downstream of bent, the deposition mass reduces sharply because of the whirlpool zone generated due to airflow boundary layer separation. In the outside of bent, the deposition ratio reduces relatively because of the airflow skewing which intensifies the airflow washing the wall of pipeline. However, in the inner side of bent, the deposition mass is the least because of the airflow boundary layer separation and the dust particles skewing along with the airflow. In theTbend, the dust deposition is influenced by the branch pipe angle and the airflow velocity. The suitable parameters of high concentration dust in ventilation conveyer are as follows: the airflow velocity of horizontal straight pipe and 90° bend pipe should be not lower than 17 m/s; and the angle ofTbend pipe should be 30°~45°, and the airflow velocity of branch pipe should be not exceeding main pipeline.