Fluid Resistance Research Articles

Large-scale fabrication of decoupling coatings with promising robustness and superhydrophobicity for antifouling, drag reduction, and organic photodegradation

It is still a challenge to achieve large-area preparation of robust superhydrophobic surfaces with strong mechanical stability. Here, a simple and low-cost method to prepare robust decoupling superhydrophobic coatings on aluminum (Al) alloys substrate has been presented. The superhydrophobicity and robustness of decoupling coatings are realized by structuring surfaces at two different length scales, with nanostructures for superhydrophobicity and microstructures for robustness. This prepared decoupling coating shows promising superhydrophobicity, with water contact angle (CA) of ∼158.4° and roll off angle (RA) of ∼3°. It also exhibits high repellency for impacting water droplets. Notably, the decoupling coating processes outstanding adhesion strength on the substrate after tape-peeling and cross-cut tests, also with promising wear resistantance after sandpaper abrasion and wear test. The friction coefficient of this decoupling coating is only ∼0.2. In addition, the robust decoupling superhydrophobic coating is applied to underwater buoyancy enhancement and fluid resistance reduction (drag reduction rate ∼30.09%). This decoupling superhydrophobic coating also displays promising self-cleaning and antifouling properties. Moreover, benefitting from the photocatalytic property of TiO2, this decoupling coating is also exploited for degrading organics to achieve seawater purification. This obtained decoupling superhydrophobic coating is expected to apply on other solids in marine fields, and the simple and eco-friendly method develops the potential practical application.

Primary prophylaxis for spontaneous bacterial peritonitis is linked to antibiotic resistance in the Veterans Health Administration.

Analyze peritoneal fluid resistance patterns in patients with a first SBP episode with/without SBPPr using the Veterans Health Administration corporate data warehouse and to evaluate national antibiograms. Corporate data warehouse data were extracted using validated International Classification of Disease-9/10 codes, culture, resistance data, and outcomes of 7553 patients who developed their first inpatient SBP between 2009 and 2019 and compared between those with/without SBPPr. Escherichia coli ( E. coli ) and Klebsiella pneumoniae ( K. pneumoniae ) sensitivity to ciprofloxacin and TMP-SMX was calculated using 2021 Veterans Health Administration antibiogram data from all states. The most common isolates were E. coli , K. pneumoniae , and Staphylococcus species. Veterans taking ciprofloxacin SBBPr had higher fluoroquinolone resistance (34% vs 14% no SBPPr, p <0.0001); those taking TMP-SMX had higher TMP-SMX resistance (40% vs 14%, p <0.0001). SBPPr patients showed higher culture positivity, greater length of stay, higher second SBP, and higher probability of liver transplant rates versus no SBPPr. Multivariable models showed SBBPr to be the only variable associated with gram-negative resistance, and SBPPr was associated with a trend toward longer length of stay. E. coli ciprofloxacin sensitivity rates were 50%-87% and 43%-92% for TMP-SMX. K. pneumoniae ciprofloxacin sensitivity was 76%-100% and 72%-100% for TMP-SMX. Among patients who developed their first SBP episode, there was a higher prevalence of antibiotic resistance in those on SBPPr, with a high rate of fluoroquinolone resistance across the Veterans Health Administration sites.

Study on the pressure wave velocity model of multiphase fluid in the annulus of dual-gradient drilling

Dual-gradient drilling technology is difficult to detect and deal with well kick, which may cause safety problems such as well control. Once a well kick occurs, the pressure in the narrow annulus increases instantaneously, so it is particularly important to clarify the transmission law of pressure wave. Taking the pressure fluctuation in the annulus of double gradient drilling as an example, considering the boundary between the inner wall of the casing annulus and the outer wall of the drill string, the fluid resistance, the flow field distribution and the multiphase flow, this paper deduces and establishes the multiphase flow pressure wave velocity model in the annulus, and compares the calculation results with the pressure wave velocity model in the circular pipe. The research shows that when the casing and drill string are in the static condition with small roughness and little difference between them, the shear stress on the inner wall of the annulus and the outer wall of the drill string can be treated as equal, and the derivation of the annulus pressure wave velocity model can be simplified. The pressure wave velocity of multiphase flow in annulus is related to casing size, drill string size and multiphase fluid properties. Among them, the gas content is the main influencing factor. With the increase of the gas content, the pressure wave velocity decreases, but the decreasing range will gradually decrease. When the solid content is small, it has little effect on the pressure wave velocity.

Study on the pressure wave velocity model of multiphase fluid in the annulus of dual-gradient drilling

Dual-gradient drilling technology is difficult to detect and deal with well kick, which may cause safety problems such as well control. Once a well kick occurs, the pressure in the narrow annulus increases instantaneously, so it is particularly important to clarify the transmission law of pressure wave. Taking the pressure fluctuation in the annulus of double gradient drilling as an example, considering the boundary between the inner wall of the casing annulus and the outer wall of the drill string, the fluid resistance, the flow field distribution and the multiphase flow, this paper deduces and establishes the multiphase flow pressure wave velocity model in the annulus, and compares the calculation results with the pressure wave velocity model in the circular pipe. The research shows that when the casing and drill string are in the static condition with small roughness and little difference between them, the shear stress on the inner wall of the annulus and the outer wall of the drill string can be treated as equal, and the derivation of the annulus pressure wave velocity model can be simplified. The pressure wave velocity of multiphase flow in annulus is related to casing size, drill string size and multiphase fluid properties. Among them, the gas content is the main influencing factor. With the increase of the gas content, the pressure wave velocity decreases, but the decreasing range will gradually decrease. When the solid content is small, it has little effect on the pressure wave velocity.

Trajectory planning method with grinding compensation strategy for robotic propeller blade sharpening application

A propeller is the main part of a water-borne carrier's drive system. Geometrical shape accuracy and sharpness on the cutting side of the propeller's blade play vital roles to minimize fluid resistance and improve transmission efficiency. For Jet Ski and small boats, the significant thickness variation along the blade edge is embedded in the lost-wax casting process. The automatic trajectory planning for the robotic propeller blade's sharpening operation is challenging due to its complicated curved shape and the tiny gaps between two connected blades. The trajectory planning for robotic grinding based on the edge thickness distribution of the standard model may result in over- or under-cutting due to the highly inconsistent shape deformation caused by the casting process. To address the aforementioned challenges, this study proposes a fully automated robot grinding system. The proposed method combines a novel trajectory planning approach based on a parametric and point cloud model with a 3D scanning on edge-based trajectory adjustment approach. Moreover, to improve the grinding accuracy, a laser-vision sensor-based detection algorithm is also developed for grinding compensation to counteract the geometrical variation caused by the casting process. The effectiveness of the proposed system is validated through numerous experimental trials using a 6-DOF industrial robot. The research findings showcase that the proposed technique is feasible, stable, and effective for robotic propeller blade edge sharpening operations.

Clinical and Laboratory Assessment of Dental Status: Age Characteristics, Dynamics of Indicators of Resistance of Oral Fluid

As a result of aging process, the state of human body homeostasis undergoes the changes. In the tooth-jaw system, such changes lead to a shift of the balance in the remodeling-demineralization processes. Their intensity and dynamics depend on the properties of oral fluid, which plays an important role for the ensuring of physiological processes of oral cavity. The purpose of the work was clinical assessment of the dental status, examination of calcium homeostasis, activity of phosphatases and protein metabolism of oral fluid in patients of different age groups and their features under conditions of dental prosthetics. 103 patients aged from 18 to 89 years were examined who were assessed for the intensity of dental caries damage (DMF index), the state of hygiene and soft tissues (OHI-S and PMA indexes). The level of total and ionized calcium, the activity of acid and alkaline phosphatases, the content of total protein, and the state of its acid-base balance (pH) were determined in the oral fluid. It was found that with the age in the oral fluid the concentration of total and ionized calcium increases, acid and alkaline phosphatases become active, the content of total protein rises against the background of a decrease the intensity of salivation, the acid-base balance shifts to the alkaline side, the mineralization of tooth enamel increases, and the risk of hard dental deposits formation increases. Age characteristics of oral fluid resistance correlate with the intensity of dental caries damage, the state of hygiene and periodontal tissues. The changes of studied parameters in persons of the older age groups correlate with the results, that were found in patients with significant tooth loss (most of them are advanced and senile). It was found that the use of prostheses for replacement of dentition defects has a positive effect on the parameters of oral fluid, which ensure the resistance of hard teeth tissues and the bone base of the alveolar processes.

Development of Biocompatible Bulk MgZnCa Metallic Glass with Very High Corrosion Resistance in Simulated Body Fluid.

Magnesium-zinc-calcium (Mg-Zn-Ca) alloys as a biomaterial have attracted much attention recently, owing to their excellent biocompatibility, similar mechanical properties to natural bone, and biodegradable properties. Despite the numerous advantages of MgZnCa alloys, the rapid degradation of magnesium proved challenging as the implant in unable to retain its structural integrity for a sufficient duration of time. For metallic glasses, the capability to produce a bulk sample that is sufficiently large for useful applications have been far less successful owing to challenging processing parameters that are required for rapid cooling. In this study, Mg65Zn30Ca5 melt-spun ribbons were produced using melt-spinning followed by spark plasma sintering under high pressure (60 MPa) at different temperatures (130-170 °C) to provide an insight into the consolidation, mechanical, and corrosion behavior. Microstructural interfaces were characterized using scanning electron microscopy while the thermal stability of the amorphous phase was characterized using differential scanning calorimetry and X-ray diffraction. Here, pellets with 10 mm diameter and 10 mm height with a complete amorphous structure were achieved at a sintering temperature of 150 °C with densification as high at ~98%. Sintering at higher temperatures, while achieving higher densification, resulted in the presence of nano-crystallites. The mechanical properties were characterized using microhardness and compression tests. The hardness values of the sintered products were relatively higher to those containing crystallite phases while the ultimate compressive strength increased with increasing sintering temperature. Bio-corrosion properties were characterized via electrochemical testing with PBS as the electrolyte at 37 °C. The corrosion results suggest that the sintered samples have a significantly improved corrosion resistance as compared to as-cast samples. More notably, SPS150 (samples sintered at 150 °C) exhibited the best corrosion resistance (35× compared to as-cast in the context of corrosion current density), owing to its single-phase amorphous nature. This study clearly shows the potential of spark plasma sintering in consolidating amorphous ribbons to near-full density bulk pellets with high corrosion resistance for bio-applications.

Negative differential thermal resistance of fluids induced by heat baths

It has recently been shown that in one-dimensional hard-point gases, there is a mechanism that induces negative differential thermal resistance (NDTR) between heat baths. We examine this mechanism in more general higher-dimensional fluids described by multiparticle collision dynamics. We consider fluids in a finite cuboid region of three-dimensional space with each end in contact with a heat bath. Based on analytical results and numerical models, we find that the mechanism underlying NDTR also works for high-dimensional fluidic systems with weak interactions and is very robust to mixed fluids. Our results significantly advance knowledge of NDTR induced by heat baths and illuminate different directions to explore in fabricating fluid thermal transistors in micro- and nanosystems.

Monitoring of Indoor Farming of Lettuce Leaves for 16 Hours Using Electrical Impedance Spectroscopy (EIS) and Double-Shell Model (DSM).

An electrical impedance spectroscopy (EIS) experiment was performed using a double-shell electrical model to investigate the feasibility of detecting physiological changes in lettuce leaves over 16 h. Four lettuce plants were used, and the impedance spectra of the leaves were measured five times per plant every hour at frequencies of 500 Hz and 300 kHz. Estimated R-C parameters were computed, and the results show that the lettuce leaves closely fit the double-shell model (DSM). The average resistance ratios of R1 = 10.66R4 and R1 = 3.34R2 show high resistance in the extracellular fluid (ECF). A rapid increase in resistance (R1, R2, and R4) and a decrease in capacitance (C3 and C5) during water uptake were observed. In contrast, a gradual decrease in resistance and an increase in capacitance were observed while the LED light was on. Comparative studies of leaf physiology and electrical value changes support the idea that EIS is a great technique for the early monitoring of plant growth for crop production.

Comparison of various structure designs of SO2-depolarized electrolysis cell

SO2-depolarized electrolysis (SDE) is the key step of the hybrid sulfur (HyS) process, which is one of the simplest thermochemical cycles for producing hydrogen by water splitting. Exploration and optimization of flow field/structure design is essential for improving the efficiency of SDE. In this work, graphite plates with different flow channels, together with porous graphite felts or carbon papers as diffusion layers are adopted to fabricate SDE cells with different structures. Evaluation of the cell structures is carried out, by comparing the SDE performance and taking into account the fluid resistance (pressure drop) of anode side. The effects of graphite felt compression ratio, hydrophilicity or hydrophobicity of carbon papers, anodic fluid flow rate, and operating temperature on the SDE performance are investigated. Square porous flow fields provided by graphite felts show excellent performance. Serpentine channel covered by hydrophobic carbon paper reveals advantages when adopted on the cathode side. Combination of above two flow fields and using them on anode and cathode sides respectively, could achieve excellent SDE performance. Under the condition of 40 °C and 360 mL/min anolyte flow rate, the current density could reach 760 mA/cm2 at the cell voltage of 1.19 V.

Correlation between Mycoplasma pneumoniae drug resistance and clinical characteristics in bronchoalveolar lavage fluid of children with refractory Mycoplasma pneumoniae pneumonia

BackgroundTo investigate the resistance-gene mutation of Mycoplasma pneumoniae (MP) in the bronchoalveolar lavage fluid of children with Mycoplasma pneumoniae pneumonia (MPP) and the clinical characteristics of refractory Mycoplasma pneumoniae pneumonia (RMPP) correlation.MethodsForty-eight children with MPP were selected and placed in RMPP and non-RMPP groups based on their clinical status – whether they had worsening clinical symptoms, persistent fever and a worsening lung image. They were also separated into drug-resistance gene mutation and non-mutated groups using nucleic acid detection. The participants’ data were collected on high-sensitivity C-reactive protein and MP-DNA loads, fever time, hospitalisation time, macrolide antibiotic application time and fever regression time after application. The differences in imaging manifestations were determined by using multivariate logistic regression to analyse the clinical characteristics of RMPP. Additionally, the correlation between drug-resistance gene mutations and the clinical characteristics of RMPP was summarised.ResultsAmong the 48 MPP children, 31 (64.6%) had A2063G and/or A2064G gene mutation, 31 (64.6%) had RMPP and 23 (74.2%) had drug-resistance gene mutation. The children in the drug-resistance gene mutation group had higher high-sensitivity C-reactive protein and MP-DNA loads, longer fever time, hospitalisation time, macrolide antibiotic application time, fever regression time after application and extrapulmonary complications. There were more symptoms and more severe changes under bronchoscopy. The difference was statistically significant (P < 0.05). Logistic multivariate regression analysis showed that the mutation of drug-resistance genes had no significant correlation with RMPP.ConclusionThe mutation rate of drug-resistance genes in children with MPP is high, the inflammatory index and MP-DNA load are high, the course of the disease is long, and the changes under bronchoscopy are severe. The occurrence of RMPP is not only determined by drug-resistance genes but may also be the result of a combination of factors.

Research of a novel fracturing-production integral fluid based on cationic surfactant

Fracturing plays an extremely important role in increasing oil and gas production, however, the fracturing flowback fluid has problems such as large volume, difficult treatment, high processing cost, and environmental pollution. In order to expand the application range and reuse of clean fracturing fluid,a fracturing-production integral fluid based on small molecule surfactants, cetyl trimethyl ammonium chloride (CTAC), salicylic acid (SA) and oleic acid amide methyl hydroxypropyl ammonium chloride (OAMDC) is proposed. At 90 °C the resistance of the fracturing-production integral fluid reached values up to 63.5 mPa·s. The surface and interface tension of the fracturing-production integral fluid broken by crude oil were 28.5 and 8.19 × 10-3 mN/m, respectively. It shows good oil flooding ability (up to 16.35 %), static oil washing rate (up to 21.5 %) and outstanding emulsification effect. Meanwhile, the application scope clean fracturing flowback fluid will be expanded to achieve its efficient and comprehensive application in the field of oilfield chemistry, thereby improving the benefits of oilfield development.

Experimental investigation into the effects of electric discharge surface modification process parameters on the biocompatibility of Ti6Al4V

Titanium alloys especially Ti6Al4V is extensively used in the fabrication of biomedical implant due to its similar mechanical properties as of bone, bio compatibility, high strength to weight ratio, better resistance to the body fluid and corrosion resistance etc. However, in order to further improve the osteointegration, anti-bacterial, anti-corrosion, and anti-wear properties, various surface modification or coating methods are often essential. Moreover, the biological behavior of surrounding cells on the implants depends on its various surface properties like surface roughness and wettability, etc. Therefore, in this paper a comprehensive experimental investigation is planned to investigate the influence of electric discharge-based surface modification process parameters on the bio-compatibility of Ti–6Al–4V. The important process parameters such as current and pulse ON time was varied at three different levels with double deionized water as the dielectric fluid to generate different functional surfaces. The areal surface roughness, wettability, surface elemental composition and morphology, etc. were analyzed in detail using scanning electron microscopy (SEM), X-Ray Diffractometry (XRD), Energy Dispersive x-ray spectroscopy (EDS). It is observed that the surface roughness values varied between 2.9 µm to 5.4 µm with respect to the variation in the pulse ON time and current. Similarly, the contact angle also varied between the hydrophilic to hydrophobic with respect to the number of days from the development of the surfaces. In addition, it is observed that a good amount of oxygen got deposited on the surface and formed various bio active titanium oxides which enhances the cell viability, cell adhesion and proliferation. The cytocompatibility tests with L929 fibroblast cells as per the ISO 10993-5, showed a maximum of cell viability up to 84.69% with 70.6633% of cell survival.

Numerical and experimental investigation of the converging embedded magnetic fluid seal with a large diameter shaft and large sealing gap

In order to enhance the pressure resistance of the ordinary magnetic fluid (MF) seal (MFS) with a large diameter shaft and large sealing gap, the converging embedded MFS (EMFS) device with a large diameter shaft and large sealing gap is designed in accordance with the principle of EMFS. A combination of numerical simulations and experimental studies is used to examine the effect of important factors such as the size of the sealing gap and the pole teeth (PT) number on the ability of the converging EMFS to pressure resistance. The findings indicate that the experimental pressure resistance of the converging EMFS with a large diameter shaft and large sealing gap is basically consistent with the theoretical pressure resistance. As the radial and axial sealing gaps increase, the pressure resistance of the converging EMFS decreases. With the increase of the number of radial PT, the pressure resistance of the converging EMFS first increases and then decreases. With the increase of the number of axial PT, the pressure resistance of the converging EMFS first increases, then decreases and then increases. The pressure resistance of the converging EMFS remains unchanged with the increase of the speed.

Numerical Study on Laminar Drag Reduction for Superhydrophobic Surfaces with Continuous V-Shaped Microstructures

Superhydrophobic surfaces have attracted great attention owing to their capacity of reducing fluid resistance. Most of the previous numerical simulations on drag reduction of the superhydrophobic surfaces have concentrated on the rectangular microstructures, whereas few studies have focused on the continuous V-shaped microstructures. Based on the gas–liquid two-phase flow theory and volume-of-field model, combined with the semi-implicit method for pressure-linked equations algorithm, the effects of laminar drag reduction for superhydrophobic surfaces with continuous V-shaped microstructures were numerically studied. Three different sizes of superhydrophobic microchannels with continuous V-shapes were simulated according to the experimental data. Results showed that the drag reduction effects of continuous V-shaped microstructures were mainly determined by the width of adjacent microstructures, with the height of the microstructures only having minimal influence. At the same time, the effects of drag reduction for superhydrophobic surfaces with continuous V-shaped microstructures were compared with those with V-shaped and rectangular microstructures. The results indicated that the effects of drag reduction for superhydrophobic surfaces with continuous V-shaped microstructures were obviously better than for those with V-shaped microstructures, whereas the superhydrophobic surfaces with rectangular microstructures were more effective in reducing their drag than those with V-shaped microstructures under the condition of the same shear-free air–water ratios. Therefore, in the preparation of superhydrophobic materials, the continuous V-shaped microstructures are recommended; in addition, increasing the microstructure width should be emphasized in the preparation of superhydrophobic materials with continuous V-shaped microstructures.

Inhibition of Mg corrosion in physiological fluids by carbonate coating

Corrosion protective coatings were grown on pure magnesium in naturally carbonated mineral water containing Ca2+ using a simple, green conversion method. Dissolution of the native corrosion product, Mg(OH)2, mediates the surface nucleation of hydroxycarbonates. The pH increase due to CO2 degassing to atmospheric pressure leads to calcium carbonate nucleation and lateral growth by the incorporation of nanoparticles in a continuous layer of calcite -Ca(Mg)CO3- microcrystals. The coated surfaces have a much improved corrosion resistance in physiological fluids, measured by EIS, weight loss, corrosion rates and hydrogen release. Cell viability/morphology assessment demonstrates that the coating is non-toxic and promotes the proliferation of osteoblastic cells.

Real-time in-situ optical detection of fluid viscosity based on the Beer-Lambert law and machine learning.

As an important physical quantity to describe the resistance of fluid to flow, viscosity is an essential property of fluids in fluid mechanics, chemistry, medicine, as well as hydraulic engineering. While traditional measurement methods, including the rotating-cylinder method, capillary tube method and falling sphere method, have significant drawbacks especially in terms of accuracy, response time and the sample must be made to move. In this work, a novel Beer-Lambert law-based method was proposed for the viscosity measurement. Specifically, this work demonstrates that viscosity can be quantitatively reflected by spectral line intensity, and castor oil was selected due to its viscous temperature properties (viscosity has been accurately measured under different temperature), and its transmission spectrum at different temperatures ranging from 10 to 50°C was detected firstly. Then, the principal component analysis (PCA) was employed to obtain the intrinsic features of the transmission spectrum. Finally, the processed data was utilized to train and verify the radial basis function (RBF) neural network. As a result, the accuracy of the predictions conducted by means of the RBF reached 98.45%, which indicates the complicated and non-linear relationships between spectra formation and viscosity can be depicted well by RBF. The results show that the real-time in-situ optical detection method adopted in this work represents a great leap forward in the viscosity measurement, which fundamentally reforms the traditional viscosity measurement methods.

Evaluation of low-gravity-solids sedimentation in non-Newtonian synthetic-based drilling fluids monitored by gamma-ray attenuation technique

ABSTRACT Drilling fluids are used in the process of drilling wellbores. They are formulated by a combination of solubles and suspended solids. During drilling, cuttings of rock formation may get in the mix. Some of them are too small and light to be removed from the fluids. They are called low-gravity solids (LGS). In no drilling situations, both solids may settle due to gravity. This project aimed to characterize the physical and rheological properties of synthetic-based drilling fluids and monitor the distribution of solids concentration in batch gravity settling experiments. The interplay of solid content and mud rheology was evaluated by pycnometry, retort, and rheological analysis. The Gamma-ray Attenuation Technique was applied to monitor the solid concentration along the test tube as a function of time. We analyzed two similar muds that slightly differed by the presence LGS The fluids presented non-Newtonian behavior, clear separation of solids in two phases and apparent viscosity changes. After 90 days, the clarified liquid region was formed between 16 and 22 cm from the bottom of the tube. This region took shape between 7 to 80 days, and the maximum solid concentration was approximately 9%. Finally, the LGS increased the fluid resistance of settling.

Role of resistance forces in Galileo’s experiments

We apply fluid resistance and rolling resistance analysis to the free fall and projectile experiments described in Galileo Galilei’s 1638 Dialogues Concerning Two New Sciences (Discorsi), and his unpublished folio 116v experiment in the Codex 72 collection. Both air resistance and rolling resistance affect the horizontal projection distance in the folio 116v experiment. Newton’s second law and the two combined resistance forces can quantitatively explain Galileo’s observations. The analysis is also applied to replication experiments made by Naylor in 1974. Quantitative agreement is achieved. Resistance forces remove a small discrepancy between observed and theoretical horizontal projectile distances that is present when air resistance and rolling resistance are ignored. The result is significant because it shows that, contrary to prior studies, resistance forces cannot be ignored when one models the folio 116v experiment. Air drag forces due to acceleration (added mass and Basset history) are negligible, but quasi-steady drag and Magnus lift are not. This exercise provides an historical perspective to the description of basic body motion: constant acceleration, uniformly increased velocity, constant inertial motion, and decomposition of two-dimensional motion into orthogonal coordinates. It also serves to give specific examples of significant ‘real-world’ effects, such as steady drag, added mass, Basset history, rolling resistance, spin drag, and Magnus lift that complicate what appears to be a simple experiment. Finally, it shows that a quantitative test of a seemingly obvious assumption can yield new insights.

Research on Key Technologies to Improve Cementing Displacement Efficiency.

The annulus has a wide and narrow clearance due to casing eccentricity in the cementing process and due to the eccentricity of casing in the process of cementing. Because the flow resistance of the drilling fluid in the wide gap is less than that in the narrow gap, the phenomena of a delayed flow or even an overall nonflow occurs in the narrow gap. Based on the existing displacement efficiency calculation model, this paper establishes the cementing displacement efficiency model under the condition of oil-based drilling fluid, explores the residual layer thickness of drilling fluid on the casing side and the sidewall side, and then links the annular displacement efficiency to the injection displacement in combination with the circulating mode resistance pressure drop formula so as to explore the change in the cementing displacement efficiency under different displacements. Considering the change in the physical parameters of annulus fluid, the change in annulus displacement efficiency is obtained. On this basis, the relationship between the wellhead cement injection flow and the annulus retention layer is studied; then, the displacement is calculated. The reasonable cementing displacement is calculated by combining the displacement with annulus displacement efficiency. The results show that the thickness of the annular detention layer increases with the increase in the casing eccentricity in the same well depth, and the growth rate of the detention layer on the wellbore side is greater than that on the casing side at the same circumferential angle. The greater the displacement, the greater the annular circulation pressure drop and circulation equivalent density, thus increasing the cementing risk. The displacement is reasonably designed. The research results in this paper have a certain guiding significance for improving the displacement rate of isolation fluid under oil-based drilling fluid conditions.