In order to obtain the impact frequency of resonant coal breaking by self-excited oscillation pulsed supercritical carbon dioxide(SC-CO_(2))jet,large eddy simulation was used to analyze the formation and development p...In order to obtain the impact frequency of resonant coal breaking by self-excited oscillation pulsed supercritical carbon dioxide(SC-CO_(2))jet,large eddy simulation was used to analyze the formation and development process of self-excited oscillation pulsed SC-CO_(2)jet,the variation of jet impact frequency in the nozzle and the free flow field,and the variation of jet impact frequency at different positions in the jet axis and under different cavity lengths.The test device of jet impact frequency was developed,and experiments were performed to verify the conclusions of the numerical simulations.The results show that the frequency of the self-excited oscillation pulsed SC-CO_(2)jet is different in the nozzle and the free flow field.In the nozzle,the frequency generated by the fluid disturbance is the same,and the jet frequency at the exit of the nozzle is consistent with that inside the nozzle.In the free flow field,due to the compressibility of CO_(2),the pressure,velocity and other parameters of SC-CO_(2)jets have obvious fluctuation patterns.This feature causes the impact frequency of the self-excited oscillation pulsed SC-CO_(2)jet to decrease gradually in the axis.Changing the cavity length allows the adjustment of the jet impact frequency in the free flow field by affecting the disturbance frequency of the self-excited oscillation pulsed SC-CO_(2)jet inside the nozzle.展开更多
Conventionally oil recovery factor is too low,which leaves great prospects for the application of enhanced oil recovery(EOR)methods to increase recovery factor.EOR methods are capital intensive and few are environment...Conventionally oil recovery factor is too low,which leaves great prospects for the application of enhanced oil recovery(EOR)methods to increase recovery factor.EOR methods are capital intensive and few are environmentally hazardous.So the paper discusses on the alternate enhanced oil recovery technique which has tremendous potential to curb the challenges of conventional EOR methods.Plasma pulse technology(PPT)aided EOR treatment is administered with an electric wireline conveyed plasma pulse generator tool that is run in the well and positioned alongside the perforations.Using energy stored in the generator's capacitors,a plasma arc is created that emits a tremendous amount of heat and pressure for a fraction of a second.This in turn creates a broad band of hydraulic impulse acoustic waves that are powerful enough to clean perforations and near wellbore damage.These waves continue to resonate deep into the reservoir,exciting the fluid molecules and increasing the reservoirs natural resonance to the degree that it can break larger hydrocarbon molecules to smaller one and simultaneously reducing adhesion tension which results in increased mobility of hydrocarbons.The plasma pulse technology has been successfully used on production as well as injection wells.It has been used often as a remedial procedure to increase well's productivity that has been on production for a period of time.This paper throws light on fundamentals of this advancing plasma pulse technology,contrasting it with recent EOR techniques.Effectiveness of treatment in increasing oil recovery,it's applicability to different reservoir types and results achieved so far are also covered in the paper.展开更多
As a member of Xenes family,germanene has excellent nonlinear saturable absorption characteristics.In this work,we prepared germanene nanosheets by liquid phase exfoliation and measured their saturation intensity as 0...As a member of Xenes family,germanene has excellent nonlinear saturable absorption characteristics.In this work,we prepared germanene nanosheets by liquid phase exfoliation and measured their saturation intensity as 0.6 GW/cm^(2) with a modulation depth of 8%.Then,conventional solitons with a pulse width of 946 fs and high-energy noise-like pulses with a pulse width of 784 fs were obtained by using germanene nanosheet as a saturable absorber for a mode-locked Erbium-doped fber laser.The characteristics of the two types of pulses were investigated experimentally.The results reveal that germanene has great potential for modulation devices in ultrafast lasers and can be used as a material for creation of excellent nonlinear optical devices to explore richer applications in ultrafast photonics.展开更多
基金Supported by National Natural Science Foundation of China(52174170,51974109)Basic Research Funds of Henan Polytechnic University(NSFRF220205)Strategic Consulting Research Project of Henan Research Institute of China Engineering Science and Technology Development Strategy(2022HENZDB03)。
文摘In order to obtain the impact frequency of resonant coal breaking by self-excited oscillation pulsed supercritical carbon dioxide(SC-CO_(2))jet,large eddy simulation was used to analyze the formation and development process of self-excited oscillation pulsed SC-CO_(2)jet,the variation of jet impact frequency in the nozzle and the free flow field,and the variation of jet impact frequency at different positions in the jet axis and under different cavity lengths.The test device of jet impact frequency was developed,and experiments were performed to verify the conclusions of the numerical simulations.The results show that the frequency of the self-excited oscillation pulsed SC-CO_(2)jet is different in the nozzle and the free flow field.In the nozzle,the frequency generated by the fluid disturbance is the same,and the jet frequency at the exit of the nozzle is consistent with that inside the nozzle.In the free flow field,due to the compressibility of CO_(2),the pressure,velocity and other parameters of SC-CO_(2)jets have obvious fluctuation patterns.This feature causes the impact frequency of the self-excited oscillation pulsed SC-CO_(2)jet to decrease gradually in the axis.Changing the cavity length allows the adjustment of the jet impact frequency in the free flow field by affecting the disturbance frequency of the self-excited oscillation pulsed SC-CO_(2)jet inside the nozzle.
文摘Conventionally oil recovery factor is too low,which leaves great prospects for the application of enhanced oil recovery(EOR)methods to increase recovery factor.EOR methods are capital intensive and few are environmentally hazardous.So the paper discusses on the alternate enhanced oil recovery technique which has tremendous potential to curb the challenges of conventional EOR methods.Plasma pulse technology(PPT)aided EOR treatment is administered with an electric wireline conveyed plasma pulse generator tool that is run in the well and positioned alongside the perforations.Using energy stored in the generator's capacitors,a plasma arc is created that emits a tremendous amount of heat and pressure for a fraction of a second.This in turn creates a broad band of hydraulic impulse acoustic waves that are powerful enough to clean perforations and near wellbore damage.These waves continue to resonate deep into the reservoir,exciting the fluid molecules and increasing the reservoirs natural resonance to the degree that it can break larger hydrocarbon molecules to smaller one and simultaneously reducing adhesion tension which results in increased mobility of hydrocarbons.The plasma pulse technology has been successfully used on production as well as injection wells.It has been used often as a remedial procedure to increase well's productivity that has been on production for a period of time.This paper throws light on fundamentals of this advancing plasma pulse technology,contrasting it with recent EOR techniques.Effectiveness of treatment in increasing oil recovery,it's applicability to different reservoir types and results achieved so far are also covered in the paper.
基金funded by the National Natural Science Foundation of China(Grant No.62005094)the Natural Science Foundation of Shandong Province(No.ZR2021MF128)+1 种基金the Key research program of Shandong Province(2020JMRH0302)the Industrial Chain Program of Shandong laser Equipment Innovation and Entrepreneurship Community(JGCYL2022-5).
文摘As a member of Xenes family,germanene has excellent nonlinear saturable absorption characteristics.In this work,we prepared germanene nanosheets by liquid phase exfoliation and measured their saturation intensity as 0.6 GW/cm^(2) with a modulation depth of 8%.Then,conventional solitons with a pulse width of 946 fs and high-energy noise-like pulses with a pulse width of 784 fs were obtained by using germanene nanosheet as a saturable absorber for a mode-locked Erbium-doped fber laser.The characteristics of the two types of pulses were investigated experimentally.The results reveal that germanene has great potential for modulation devices in ultrafast lasers and can be used as a material for creation of excellent nonlinear optical devices to explore richer applications in ultrafast photonics.
