| The phenomenon of two-phase pulsating flow widely exists in the industrial producingprocess. For example, on and off of valves and pumps in the boiler tubes, and nuclear powerships traveling in the ocean, they all include the two-phase pulsating flow. And the rectangularchannel will be more and more widely used, so in this paper, the resistance characteristics oftwo-phase pulsating flow in rectangular channel were experimentally investigated.The experiments contained two parts: the part under steady state and the part underpulsating conditions. Using de-ionized water and Nitrogen, experiments were conducted inthe horizontal rectangular channel, considering of the influence acting on void fraction, flowpattern and resistance characteristics caused by pulsating conditions. The test section is madeof PMMA. It is2000mm long, the size of cross section of it is W×H=40mm×3mm. Theranges of measured parameters are as follows: the system pressure is0.1MPa; the temperatureis14～20℃; the gas flow is0.01～0.45kg/h; the liquid flow is0.034～0.92m3/h; thepulsating period of liquid flow is10.9～20.3s; the pulsating amplitude of liquid flow is0.06～0.28m3/h.For instantaneous void fraction, the influence acting on it caused by pulsating conditionswas investigated by using the methods of image analysis and data processing. It was beenfound that: when the liquid flow is certain, the average value of instantaneous void fraction αwas increased with the increasing of volumetric void fraction β, and relationship between αand β gradually became linear relationship; when the gas flow is certain, the average of α wasgenerally increased with the increase of pulsating amplitude of liquid flow, only went down atthe pulsating amplitude of27%.For flow pattern, the influence acting on it was investigated by using the observationalmethod, and it was found that: under the steady state, because of dimensional characteristicsof the rectangular channel, flow pattern in the rectangular channel was not abundant. Onlybubbly flow, slug flow and churn flow; under the unsteady state, the flow pattern changedaround the peak and valley caused by the pulsating conditions.In the last part of this paper, resistance characteristics in the horizontal rectangularchannel under steady state and pulsating conditions were investigated. The influence acting on it which caused by pulsating period, pulsating amplitude, the gas flow and liquid flow wasfocused on. It was found that: under the steady condition, the two-phase pressure dropgradient was increased with the increasing of gas flow and liquid flow, and the influencecaused by gas flow was less than the one of liquid flow; under the pulsating condition, theaverage pressure drop gradient was increased with the increase of gas flow and average liquidflow, but did not change significantly with the change of pulsating amplitude. It means thatpulsating amplitude has little effect on the pressure drop gradient. |
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