吸收式冷凍系統的吸收器，其對整體熱傳效率上有很重要的影響。於目前的研究指出，由於吸收器是在真空中進行吸濕冷卻運作，針對探討吸收劑與冷媒的吸收率，大多採數值模型或端點狀態判斷，其實際過程仍未被完全瞭解，故不能有效分析；且亦指出液膜動力學於吸收器影響甚鉅。考量到真空下，光學量測儀器不易放置於腔體內運作，而超音波探頭有體積小、同為非接觸式量測方法等優點，故本研究主要為使用超音波探頭，依序進行溴化鋰水溶液聲速量測、液膜厚度量測，確立探頭的實用性後，將於吸收器上建立可即時量測液膜厚度的超音波技術，配合以人為擾波之方式於吸收器表面產生波動液膜，並觀測波動的成形。未來將應用於監控吸收式冷凍系統中吸收器表面溴化鋰液膜之厚度及波動，以期望找出最佳之擾波效率。

The absorber of absorption-refrigeration system is a critical component in entire system efficiency of heat transfer. The recent research indicate that the study about absorption of absorbent and refrigerant is mostly applying numerical analysis model or local state to investigate the heat transfer efficiency. But the absorber generally works in vacuum, the process of moisture absorption cannot be realized accurately. Thus, the analytic study method cannot be used effectively. And the recent research also indicate that liquid-film hydrodynamics has a great effect on absorption process. Because the optic could not be applied in vacuum, the ultrasonic transducer which have some advantage like small volume, and non-contact measurement mode , were considered to apply in this present study. We mainly applied transducer to measure liquid’s acoustic velocity and liquid film thickness in order ,and ensured the practicality of transducer. And then, we would build the ultrasonic measurement system in the absorber to measure the film thickness instantaneously. With trigging wavy film on absorber surface by manually-controlled excitation, the effects of wave form and excitation frequency are investigated experimentally.

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