| Gas-liquid cyclone separation technology is widely used in petrochemical,aerospace and other fields.During the operation of gas-liquid cyclone separator,power input is needed,and the instantaneous flow of power sources such as reciprocating pumps shows a pulsating output state during the operation.In addition,the resonance of the fluid in the pipeline and the periodic oscillation of the flow control device will also produce fluid pulsating flow.Therefore,the inlet flow rate of the gas-liquid cyclone separator presents a fluctuating change under this condition,and the distribution law of the internal flow field of the cyclone separator is quite different from that under the stable flow rate,resulting in a significant change in the gas-liquid separation performance.Conventional gas-liquid cyclone separators are mostly suitable for the condition of constant inlet flow rate,and it is difficult to guarantee the gas-liquid separation performance under the condition of fluctuating inlet flow rate.Therefore,it is of great significance to study the flow field characteristics of gas-liquid cyclone separator and the dynamic behavior of discrete bubble coalescence and fragmentation under pulsating conditions for revealing the mechanism of gas-liquid separation in the swirl field and guiding the design of new gas-liquid cyclone separator under pulsating conditions.In this paper,the fluid domain model of the traditional gas-liquid cyclone separator is established to study the variation law of gas concentration distribution,velocity and pressure in the gas-liquid cyclone separator under the conditions of constant inlet flow and pulsating variation,respectively.Through comparative analysis,the main factors affecting the gas-liquid cyclone separation performance of pulsating inlet liquid are mastered.Based on the cyclone separation theory and the distribution law of gas-liquid two-phase flow in the cyclone under the inlet pulsation condition,a structure of a steady flow gas-liquid cyclone separator suitable for inlet pulsating liquid inlet conditions is designed.By using the computational fluid dynamics method,the flow rate fluctuates in the range of 3.72 m~3/h–4.28m~3/h.Under this pulsating condition,the internal flow field characteristics and separation performance of the steady-flow gas-liquid cyclone separator are numerically simulated and analyzed.And the influence laws of different pulsating frequencies,amplitudes,gas-liquid ratios and shunt ratios on the internal velocity field,pressure field and concentration field distribution characteristics of the steady-flow gas-liquid cyclone separator are mastered.Compared with the traditional column type gas-liquid cyclone separator,the separation efficiency of the steady flow gas-liquid cyclone separator is increased by 15.93%under the same inlet pulsating inlet conditions.Based on the variation of gas-liquid separation efficiency with time of gas-liquid cyclone separator under pulsating liquid inlet condition,in stable period,a dimensionless evaluation method for gas-liquid separation efficiency is formed under pulsating condition.Combined with the dimensionless efficiency calculation method and orthogonal test method,the influence of different operating parameters and different pulsation parameters on the separation effect is mastered.The optimal structural parameters of the steady flow gas-liquid separator under specific working conditions are obtained,and the separation efficiency reaches 90%under the parameters.According to the optimized size and structure of the steady-flow gas-liquid cyclone separator,the indoor visualization experimental prototype was produced.With the help of high-speed camera experiment technology,the visualization experimental system of gas-liquid two-phase cyclone separation process based on pulsating liquid inlet conditions was constructed.Using image contour recognition technology,the flow pattern distribution is identified and divided in the whole pulsating period.Taking the air content of section as the evaluation index,the evaluation model of gas-liquid two-phase flow structure under pulsating inlet conditions is constructed,which provides a reference for revealing the gas-liquid two-phase flow law and separation mechanism in the process of swirl separation under pulsating inlet conditions.Using a visual experimental device,the discrete bubbles in the pulsating flow field are used as the research object.The dynamic behaviors of collision and coalescence,shear fracture and tensile splitting between bubbles under pulsating liquid inlet conditions are systematically analyzed.And the influence law of bubble transport behavior on separation efficiency is masteredThe gas-liquid separation performance test indoor test system under pulsating fluid inflow condition was constructed.Based on the optimized structure of steady-flow gas-liquid cyclone separator,the gas-liquid cyclone separation performance test under pulsating condition was carried out.According to the influence of different steady-flow tube forms and different inverted cone shapes on separation efficiency,experimental tests were carried out to determine the optimum structural parameters of steady-flow gas-liquid cyclone separator.The optimum structural parameters obtained by experiments are consistent with the orthogonal test results,which verifies the accuracy of the orthogonal test results.Under different split ratio,gas-liquid ratio and pulsating frequency,the gas-liquid separation performance experiments were carried out,and the optimal operating parameters of steady flow gas-liquid cyclone separator under pulsating condition were obtained.The indoor test results show that the simulation results and the test results are in good agreement,which verifies the rationality of the structural design of the steady-flow gas-liquid cyclone separator and the correctness of the numerical simulation results.It provides a theoretical basis for the structural design and performance evaluation of the gas-liquid cyclone separator. |
PDF Full Text Request