化工进展
化工進展
화공진전
CHEMICAL INDUSTRY AND ENGINEERING PROGRESS
2014年
9期
2266-2272,2285
,共8页
吴静%李选友%陈宝明%王瑞雪%高玲
吳靜%李選友%陳寶明%王瑞雪%高玲
오정%리선우%진보명%왕서설%고령
干燥%传热%测量%间接加热%列管回转干燥机
榦燥%傳熱%測量%間接加熱%列管迴轉榦燥機
간조%전열%측량%간접가열%렬관회전간조궤
drying%heat transfer%measurement%indirect heating%tube rotary dryer
在对列管回转干燥机内传热过程进行深入分析的基础上,设计了简便、可靠的实验系统,并运用非稳态传热理论导出列管壁面与物料颗粒间的传热系数与被测量参数的关系式,从而建立了一套用于间接加热式列管回转干燥机的加热管壁面与物料颗粒间传热系数的测试方法。实验装置的传热系数测量结果显示,列管壁面与颗粒间的瞬时传热系数随筒体转动呈现周期性的变化规律,随着列管位置的升高,传热系数呈逐渐降低的趋势。通过对测试结果的误差分析表明,对传热系数测量精度影响最大的因素是紫铜管表面积,其余依次为壁面升温速率、加热电流、列管壁面温度和物料温度的测量。对常见的6种运行工况的传热系数测试结果进行了可靠性分析,结果表明,所产生的最大相对误差小于3.5%,壁面升温速率的测量误差是总误差的主要构成部分。
在對列管迴轉榦燥機內傳熱過程進行深入分析的基礎上,設計瞭簡便、可靠的實驗繫統,併運用非穩態傳熱理論導齣列管壁麵與物料顆粒間的傳熱繫數與被測量參數的關繫式,從而建立瞭一套用于間接加熱式列管迴轉榦燥機的加熱管壁麵與物料顆粒間傳熱繫數的測試方法。實驗裝置的傳熱繫數測量結果顯示,列管壁麵與顆粒間的瞬時傳熱繫數隨筒體轉動呈現週期性的變化規律,隨著列管位置的升高,傳熱繫數呈逐漸降低的趨勢。通過對測試結果的誤差分析錶明,對傳熱繫數測量精度影響最大的因素是紫銅管錶麵積,其餘依次為壁麵升溫速率、加熱電流、列管壁麵溫度和物料溫度的測量。對常見的6種運行工況的傳熱繫數測試結果進行瞭可靠性分析,結果錶明,所產生的最大相對誤差小于3.5%,壁麵升溫速率的測量誤差是總誤差的主要構成部分。
재대렬관회전간조궤내전열과정진행심입분석적기출상,설계료간편、가고적실험계통,병운용비은태전열이론도출렬관벽면여물료과립간적전열계수여피측량삼수적관계식,종이건립료일투용우간접가열식렬관회전간조궤적가열관벽면여물료과립간전열계수적측시방법。실험장치적전열계수측량결과현시,렬관벽면여과립간적순시전열계수수통체전동정현주기성적변화규률,수착렬관위치적승고,전열계수정축점강저적추세。통과대측시결과적오차분석표명,대전열계수측량정도영향최대적인소시자동관표면적,기여의차위벽면승온속솔、가열전류、렬관벽면온도화물료온도적측량。대상견적6충운행공황적전열계수측시결과진행료가고성분석,결과표명,소산생적최대상대오차소우3.5%,벽면승온속솔적측량오차시총오차적주요구성부분。
This paper presented a simple and reliable device system for the measurement of heat transfer coefficient between the immersed tube’s surface and particles in an indirect heating tube rotary dryer,based on analysis of heat transfer process in a tube rotary dryer. A mathematical model to derive heat transfer coefficient from the measured parameters was developed based on the unsteady heat transfer performance. Periodical instantaneous heat transfer coefficient between tube’s surface and particles was observed as the tube rotating with the cylinder. Low heat transfer coefficient was observed at the high position when the tube was immersed in the particle phase. Analysis of error transfer showed that the accuracy of heat transfer coefficient was sensitive to the measurement accuracy of tube surface area,tube’s surface temperature increasing ratio,electric current,temperatures of tube surface and materials. Test results also demonstrated that under the common six operating conditions in this paper,the developed measuring approach yielded high accuracy of heat transfer coefficient with relative error less than 3.5%,and the total measurement error was mainly composed of the error of tube’s surface temperature increasing ratio.