Experimental Study On The Effect Of Swing On The Absorption Of Water Vapor Into Falling Film Of LiBr-H₂O

There is a large amount of waste heat available for marine diesel engines while the ship is sailing,and absorption chillers can effectively recover and use these waste heat,but the swaying motion of the ship will affect the efficiency of the falling film absorption of the absorber.At present,the research on the influence of swing on the absorption of falling film is still very scarce.Therefore,further research on the effect of swing on falling film absorption not only has important academic value,but also has good application prospects.In this thesis,the characteristics of flow pattern change,temperature distribution and heat and mass transfer in the absorption of falling film of absorber under different swing conditions will be studied.First of all,in this thesis,the components of the absorption refrigeration unit are designed through theoretical thermal calculation.An absorption refrigeration experiment platform with LiBr-H2O as the refrigerant working pair is built on a six-degree-of-freedom swing table.In order to visualize the absorption of falling film in the absorber,a falling film tube in the absorber is replaced by a transparent glass tube.The experiment mainly studied the effect of different rocking conditions on the refrigeration performance from the perspective of the absorber.Then,under different flow rate and rolling conditions,the changes of flow pattern and temperature distribution during the absorption of falling film in the vertical tube of the absorber were photographed with high-speed camera and infrared thermal imager,respectively.The changes of flow pattern and temperature field under different experimental conditions and their effects on the absorption performance were analyzed.Experiments show that:(1)With the increase of the solution flow rate,the falling film flow appears as a stable laminar flow,"slubby"wave flow,combined wave flow,and liquid film shedding,respectively.(2)The higher the sway frequency and the larger the sway angle,the greater the disturbance to the falling film.When the falling film is laminar "flow,the greater the disturbance,the more absorption heat is released.(3)When falling film absorbs refrigerant vapor in the vertical tube of the absorber,there are two high-temperature regions,in which the temperature rise of the first region is larger.Finally,the relationship between the thermal coefficient and the different experimental conditions is fitted after the experiments.The effect of solution flow rate,heating temperature and cooling temperature on the falling film absorption performance of the absorber under different swing states was studied.It is shown that:(1)When the flow is smooth laminar,the larger angle swing is more conducive to the heat and mass transfer of the absorber.When the flow rate is larger,the smaller angle swing is benefit to the heat and mass transfer of the absorber(2)The higher the heating temperature and the lower the cooling temperature,the greater the heat and mass transfer flux of the absorber.There is a strong correlation between the fitting formula and the experimental results,which is helpful to practical application.