Equivalent Resistance Research Articles

A similarity method to correct cooling effectiveness from a scaled turbine blade experiment

The cooling effectiveness of a turbine blade is conventionally validated through scaled model experiments which involve the challenge of thermal similarity. To ensure accurate prediction of cooling performance in a real engine, it is necessary to investigate the dimension scaling effect and establish a reliable correction method for the cooling effectiveness obtained from the experiment. This paper presents a novel method derived from a one-dimensional heat transfer model to correct the scaling effects on thermal similarity. A group of experiments with a dummy blade is conducted to verify the feasibility and accuracy of the correction method. Results show the dissimilarity between scaled articles due to geometry dimension, material thermal properties, and alignment of the thermal barrier coating. A down-scaled model has higher cooling effectiveness than its full-length counterpart because of the enhanced internal convective heat transfer and reduced external surface heat transfer. In addition, dissimilarity due to mismatched heat conductivity of blade material and surface convective heat transfer coefficient can be corrected using Biot number replacement. Misalignment of thermal barrier coating can be replaced by a pseudo-blade metal of equivalent heat resistance and wall thickness including the metal and coating layer. Experimental result from a scaled model is corrected to improve the prediction accuracy of its full-length performance. Corrected cooling effectiveness matches its prototype within an uncertainty of 10 %. The present method is applicable to evaluate gas turbine components by means of scaled model experiments.

Local outlier factor based condition monitoring for sub-module capacitors in modular multilevel converters

Modular multilevel converters (MMC) as a key technology for future power grids is rapidly developing. The failure rate of sub-module (SM) capacitors is only lower than that of power devices in MMC, so accurate evaluation of the reliability of capacitors is crucial for the safe operation of MMC. Both the increase of equivalent series resistance (ESR) and decrease of equivalent series capacitance (ESC) are features for capacitor deteriorating. ESC or ESR of the capacitor reaching to limited values indicates that the end of its lifespan and it must be replaced. Most of contemporary researches only focus on ESC or ESR. This article considering the characteristics of both ESC and ESR, proposes a method for monitoring the status of SM capacitors based on machine learning algorithm: local outlier factor (LOF). By utilizing the existing SM switching function and capacitor voltage signals within a fundamental frequency cycle in the control system of MMC, the proposed strategy can not only monitor the faulty capacitors, but also can sort the degrees of abnormal states of capacitors, and the strategy is applicable to MMC with single and multiple types of SM topologies. The proposed method is verified by the hybrid MMC model on Matlab/Simulink.

A new CMOS-memristor based D-latch with fewer components

In order to study the function of memristor in new devices, a new D-latch is proposed in this paper, which is composed of threshold-type memristor, transistor, resistor and NOT gate. The proposed D-latch uses fewer components than previous. The transistor controls the on-off of the signal, and NOT gate changes the resistance state of memristor. The voltage divider circuit composed of memristor and resistor realizes the latching function. To verify the D-latch, a modified threshold-type memristor emulator circuit (MEC) is proposed. The proposed MEC is composed of operational amplifier, multiplier and second-generation current conveyor. The MEC is a voltage-controlled memristor that can realize floating input. The equivalent resistance of MEC has two kinds of high resistance and low resistance, which change with the polarity of the voltage. The MEC has the characteristic of non-volatility, that is, the resistance state of the circuit remains when the input signal is withdrawn. Through simulation analysis and experimental verification, both circuits have good performance.

Two-point resistances in symmetric bracelet resistor networks: accurate estimates and exact expressions

Resistor networks, used to model new types of natural or artificial matter, also provide generic examples for practising the methods of physics for obtaining estimates, revealing the main properties of a system and deriving exact expressions. Symmetric bracelet resistor networks are constructed by connecting n identical resistors in a circle, and then connecting two such circles by another set of n identical resistors. First, using van Steenwijk’s method, we establish that the equivalent resistance or two-point resistance (TPR) between any two nodes is derived when the layer-to-layer resistance R 0n is known. We then determine R 0n by an elementary recurrence relation which converges rapidly to its large n limit. Using this reference value of R 0n , accurate estimates of other TPRs follow for all values of n, characterised by a leading 1/n variation. In addition, exact explicit expressions of the TPRs can be calculated for any value of n. These networks, prototypes of three-dimensional networks considered in research, can be used to illustrate the diversity of the physical approach, the power of elementary methods, and to learn to be comfortable with approximations. Easy to make and use for experimental tests, they can support hands-on activities and conceptual changes.

Challenges in Measurement of Low-Value ESL and ESR of High-Performance PFN Capacitors for Klystron Modulator

In the high voltage line type pulse modulators, Pulse Forming Network (PFN) capacitors are one of the important components. These capacitors operate at peak kilo ampere current range and at repetition rate in the range of a few hundred hertz. The performance of these capacitors is critical w.r.t. overall system performance, and they are required to operate at high power density and low losses with high reliability. The Equivalent Series Inductance (ESL) and Equivalent Series Resistance (ESR) are two critical parameters that affect the performance of these capacitors. PFN modulator demands a capacitor of very low ESL and ESR for reliable operation and generation of high-voltage pulses. Higher ESR value adversely affects the performance of the capacitor by raising its temperature and thus deteriorating its life. ESL value does not directly affect life, but it affects the quality of high voltage pulse. In RRCAT, the PFN capacitors purchased from Indian manufacturers were showing high-temperature rise and failures. Therefore, new capacitors were designed to have lower ESL and ESR values. Measurement of ESL and ESR is important to evaluate the performance of the capacitors. The low value of these parameters makes their measurement a challenging task and requires special techniques. For low values of ESL and ESR (less than 100 mΩ) measurement, a differential measurement technique was used in which modification and different layouts were explored to improve the repetitive accuracy of the measurements. The differential ESR and ESL measurement techniques with more emphasis on the low-value ESR measurement will be discussed in the paper.

Facile and Nondestructive Transformation of Intrinsic Hydrophobic Behavior of a Carbon Nanotubes Sheet to Hydrophilic.

It is imperative to induce hydrophilicity in intrinsically hydrophobic carbon nanotubes (CNTs) without losing their superior properties for applications that specifically deal with aqueous media. A method for transforming a CNTs sheet from hydrophobic to hydrophilic by treatment with N-methyl-2-pyrrolidone (NMP) is explored. The NMP-treated CNT sheets are assessed based on complementing characterization, and it is concluded that the binding of NMP to a CNTs surface is through noncovalent interaction without the incorporation of defects in CNTs. The induced hydrophilicity in the CNTs sheet is stable for water exposure over a longer duration while it displays a semireversible nature upon heat treatment. The mechanical and electrical properties of the NMP-treated CNTs sheet revealed enhancement in the tensile strength from 221 to 421 MPa while maintaining a good electrical conductivity of ∼1.22 × 104 S/m because of the improved interfacial properties. The hydrophilic CNTs exhibited excellent adsorption capacity for methylene blue dye. The NMP-treated CNTs sheets demonstrated their suitability in flexible hybrid supercapacitor (FHSC) devices with improved electrochemical performance with enhancement in the capacitance from 5.4 to 7.6 F/g and a decrease in the equivalent series resistance from 53 to 34 Ω compared to pristine CNTs-based devices. These solid-state FHSC devices displayed excellent cyclic charge-discharge performance along with robust behavior over thousands of bending cycles without significant performance degradation. The excellent dye removal capability and superior electrochemical performance of the NMP-treated CNTs sheet is a consequence of their improved interface with aqueous media, which is governed by the hydrophilic nature of the CNTs sheet.

Study on Transmission Attenuation Characteristics of Abnormal Discharge Current in Transmission Lines

In order to analyze the transmission characteristics of abnormal discharge current in transmission lines, considering the frequency-dependent characteristics of line parameters, the transmission of abnormal discharge micro-current is studied theoretically and analyzed with examples. Then, ATP-EMTP is used to establish a hidden danger micro-current transmission model for the elevated line, and the micro-current transmission situation is simulated. The influence of frequency and different voltage levels on the hidden danger micro-current transmission characteristics is mainly considered. The results show that the higher the frequency of the initial signal, the larger the equivalent resistance and the smaller the equivalent inductance of the line. The frequency has little effect on capacitance and conductance. The attenuation constant of high-voltage class lines with multiple split wires is greater than that of low voltage class lines with single split wires, and the attenuation constant only increases slightly with the increase of split wires.

On-Chip Micro Temperature Controllers Based on Freestanding Thermoelectric Nano Films for Low-Power Electronics

HighlightsDense and flat freestanding Bi2Te3-based thermoelectric nano films were successfully fabricated by sputtering technology using a newly developed nano graphene oxide membrane as a substrate.On-chip micro temperature controllers were integrated using conventional micro-electromechanical system technology, to achieve energy-efficient temperature control for low-power electronics.The tunable equivalent thermal resistance enables an ultrahigh temperature control capability of 100 K mW−1 and an ultra-fast cooling rate exceeding 2000 K s−1, as well as excellent reliability of up to 1 million cycles.

Assessment of bioimpedance spectroscopy devices: a comparative study and error analysis of gold-plated copper electrodes

Objective. Bioimpedance spectroscopy (BIS) is a non-invasive diagnostic tool to derive fluid volume compartments from frequency dependent voltage drops in alternating currents by extrapolating to the extracellular resistance (R 0) and intracellular resistance (R i). Here we tested whether a novel BIS device with reusable and adhesive single-use electrodes produces results which are (in various body positions) equivalent to an established system employing only single-use adhesive electrodes. Approach. Two BIS devices (‘Cella’ and the ‘Body Composition Monitor’ [BCM]) were compared using four dedicated resistance testboxes and by measuring 40 healthy volunteers. In vivo comparisons included supine wrist-to-ankle (WA) reference measurements and wrist-to-wrist (WW) measurements with pre-gelled silver/silver-chloride (Ag/AgCl) electrodes and WW measurements with reusable gold-plated copper electrodes. Main results. Coefficient of variation were <1% for all testbox measurements with both BIS devices. Accuracy was within ±1% of true resistance variability, a threshold which was only exceeded by the Cella device for all resistances in a testbox designed with a low R 0/R i ratio. In vivo, WA-BIS differed significantly between BIS devices (p < 0.001). Reusable WW electrodes exhibited larger resistances than WW-BIS with Ag/AgCl electrodes (R 0: 738.36 and 628.69 Ω; R i: 1508.18 and 1390 Ω) and the relative error varied from 7.6% to 31.1% (R 0) and −15.6% to 37.3% (R i). Significance. Both BIS devices produced equivalent resistances measurements but different estimates of body composition both in silico and in WA setups in vivo, suggesting that the devices should not be used interchangeably. Employing WW reusable electrodes as opposed to WA and WW measurement setups with pre-gelled Ag/AgCl electrodes seems to be associated with measurement variations that are too large for safe clinical use. We recommend further investigations of measurement errors originating from electrode material and current path.

RESnet: 3D direct-current resistivity simulation using the equivalent resistor network circuit

Thin and highly conductive objects are challenging to model in 3D direct-current (DC) problems because they often require excessive mesh refinement that leads to a significant increase in computational costs. RESistor network (RESnet) is a novel algorithm that converts any 3D geo-electric simulation to solving an equivalent 3D resistor network circuit. Two features of RESnet make it an attractive choice in the DC modeling of thin and conductive objects. First, in addition to the conductivity with units of Siemens per meter (S/m) defined at the cell centers (cell conductivity), RESnet allows conductive properties defined on mesh faces and edges as face conductivity with units of S and edge conductivity with units of S·m, respectively. Face conductivity is the thickness-integrated conductivity, which preserves the electric effect of sheet-like conductors without an explicit statement in the mesh. Similarly, edge conductivity is the product of the cross-sectional area and the intrinsic conductivity of a line-like conductive object. Modeling thin objects using face and edge conductivity can avoid extremely small mesh grids if the DC problem concerns electric field responses at a much larger scale. Second, once the original simulation is transformed into an equivalent resistor network, certain types of infrastructure, similar to above-ground metallic pipes, can be conveniently modeled by directly connecting the circuit nodes, which cannot interact with each other in conventional modeling programs. Bilingually implemented in MATLAB and Python, the algorithm has been made open source to promote wide use in academia and industry. Three examples are provided to validate its numerical accuracy, demonstrate its capability in modeling steel well casings, and indicate how it can be used to simulate the effect of complex metallic infrastructure on DC resistivity data.

Waste heat recovery from the biomass engine for effective power generation using a new array-based system

Thermoelectric generator (TEG)-thermosyphon-based heat recovery system (HRS) for harvesting the heat from the high temperature sources is a well-known technology for power generation. However, various thermal resistances (a total of nine) are involved in the thermosyphon-based HRS between the heat sources and TEGs which generate irreversibility that ultimately reduces its performance. In this work, a new design of HRS i.e. TEG-array-based is proposed for effective power generation even at low temperatures of sustainable heat source by minimizing the thermal resistances. This TEG-array-based HRS is driven by a salt gradient thermal storage device (SGTSD) which is used for efficiently recovering and storing of sustainable waste heat generated from a biomass(renewable energy)-based engine-generator. The proposed system is experimentally studied to analyse the temperature variations in SGTSD, characteristics of sustainable waste heat temperature, and performance features of TEGs in terms of obtained electrical parameters, output power and conversion efficiency. The experimental results showed that the maximum open circuit voltage, output power and conversion efficiency of TEG are obtained as 81.62V, 7.438W and 4.63\\% respectively. With this proposed system, seven thermal resistances (out of total nine) are totally eliminated while the others two are lowered that leads to effectively transfer the energy from sustainable heat source to TEGs via minor equivalent thermal resistance of 0.01198oC/W. The proposed system is found to be capable of charging a 12 V, 80 Ah heavy-duty battery for real life applications.

‘Out of the glovebox’ studies of a multifunctional [Gd3+‐Ho3+‐Dy3+]:CsPbI2.7Br0.3 perovskite semiconductor system for energy applications

AbstractBACKGROUNDThis work deciphers the first report on the treble lanthanide‐doped perovskite heterosystem [Gd3+‐Ho3+‐Dy3+]:CsPbI2.7Br0.3 (GHD:C‐PVSK) and subsequently explores its prospects for solar cells, energy generation, and charge storage.RESULTSGHD:C‐PVSK remained optically active for a period of 28 days with a band gap energy of 1.62–1.76 eV. The developed perovskite material possesses cubic phase with typical ABX3 geometry and the subsequently deposited thin films have compact morphology. As a light absorber layer, a GHD:C‐PVSK‐based solution‐processed perovskite solar cell executed an efficiency of 15.11% and an improved fill factor of 71.25%. In electrocatalytic assays, GHD:C‐PVSK emerged as a bifunctional catalyst for oxygen and hydrogen generation with greater tendency towards pure hydrogen production, exuding overpotential (ηHER) – that is, 143 mV and 123.4 mV dec−1 of the Tafel slope value. With a remarkable service life of 100 min inside the electrolyte, the GHD:C‐PVSK electrode was characterized by its excellent charge storage. It has a unit capacity of 383 mA h g−1 and is marked by reduced equivalent series resistance (Rs) of 0.66 Ω.CONCLUSIONThrough photoelectrical and electrical analysis, GHD:C‐PVSK has emerged as a sustainable and energy‐efficient material that can be stabilized by suitable thermal modulation and lanthanide doping. © 2024 Society of Chemical Industry (SCI).

An enhanced perception health state assessment method for subway sliding plug door transmission system

The monitoring data (current and rotational speed) of the subway sliding plug door transmission system changed positively and negatively with the acceleration and weight of the door. How to perceive the changes is a challenging problem in the health state assessment of transmission system. To address this problem, an enhanced perception health state assessment method was proposed for the transmission systems. In the method, firstly, the equivalent resistance force is calculated by monitoring the current and rotational speed data according to mechanical dynamic knowledge. Secondly, the sensitive features of normal and abnormal states are screened out from the enhanced dataset constructed by current, rotational speed data, and equivalent resistance force data. Finally, the health state of the transmission system is assessed using an integrated learning algorithm. The effectiveness of the method is verified by benchmark experimental data, and the results indicate that the method has a higher accuracy with four classifiers and a broader suitable range with varying door acceleration and weight.

N-type semiconductor [Gd3+-Ho3+-Dy3+]:SnO2 driven functionality enhancement in energy systems associated with photovoltaic and electrochemical contraptions

Current work reports the sustainable synthesis and application of the novel n-type [Gd3+-Ho3+-Dy3+]:SnO2 semiconductor material expressing band gap energy narrowing upon lanthanide triple doping. The band gap energy of this material spanned around 3.8–3.9 eV. Rare earth doped SnO2 material has tetragonal rutile crystalline geometry, space group P42/mnm, and 59.46 nm particle size. Thin films for this material have remarkable coverage. Using this material as an electron transport layer inside all inorganic perovskite device resulted in a negligible hysteresis leading to remarkable power conversion efficiency of 14.16 %, fill factor 80 %, short circuit current 16.48 mA cm−2, and an open circuit voltage of 1.02 V [Gd3+-Ho3+-Dy3+]:SnO2 decorated nickel foam electrode expressed double layer mechanism of electrical charge storage gaining a specific capacitance of 689 F g−1 in 0.1 M NaCl electrolyte at 10 mV/s. Excellent electronic and ionic conductivity was expressed by impedance studies with equivalent series resistance (Rs) of as low as 0.11 Ω. Furthermore, the electro-catalytic water splitting results exhibited the auspicious of this material as an HER catalyst with lower overpotential and Tafel slope values of 140 mV and 125.5 mV dec−1, respectively. The developed material is a suitable candidate for advanced energy applications marked by sustainability and economic viability.

The Effect of Restoration Thickness on the Fracture Resistance of 5 mol% Yttria-Containing Zirconia Crowns.

To determine what thickness of 5 mol% yttria zirconia (5Y-Z) translucent crowns cemented with different cements and surface treatments would have equivalent fracture resistance as 3 mol% yttria (3Y-Z) crowns. The study included 0.8 mm, 1.0 mm, and 1.2 mm thickness 5Y-Z (Katana UTML) crowns and 0.5 and 1.0 mm thickness 3Y-Z (Katana HT) crowns as controls. The 5Y-Z crowns were divided among three treatment subgroups (n = 10/subgroup): (1) cemented using RMGIC (Rely X Luting Cement), (2) alumina particle-abraded then luted with the same cement, (3) alumina particle-abraded and cemented using a resin cement (Panavia SA Cement Universal). The 3Y-Z controls were alumina particle-abraded then cemented with RMGIC. The specimens were then loaded in compression at 30° until failure. All 5Y-Z crowns (regardless of thickness or surface treatment) had a similar to or higher fracture force than the 0.5 mm 3Y-Z crowns. Only the 1.2 mm 5Y-Z crowns with resin cement showed significantly similar fracture force to the 1 mm 3Y-Z crowns. In order to achieve a similar fracture resistance to 0.5 mm 3Y-Z crowns cemented with RMGIC, 5Y-Z crowns may be as thin as 0.8 mm. To achieve a similar fracture resistance to 1.0 mm 3Y-Z crowns cemented with RMGIC, 5Y-Z crowns must be 1.2 mm and bonded with resin cement.

A thermal assessment simplification exploration for the structural constraint effect on bearing temperature

Although an extensive research effort on the structural constraint role in bearing heating was done by scholars, often many researchers either neglected the sub structure effect for model simplification or considered more influencing factors to construct a complicated thermal model for higher evaluation precision. As a result, a lightweight and accurate assessment has been not available so far. Furthermore, they usually only made some basic assumptions and qualitative analyses when creating and improving the thermal predictive models to explore the heat transfer of bearings, and hence their findings usually lack sufficient theoretical supports, especially the quantitative bases. For an efficient assessment, this paper devotes to exploring how the structural constraint impact on the heat conduction of bearings, and accordingly present a more practical thermal grid to evaluate bearing heating efficiently. Firstly, the structure and installation notes of bearings were statistically analyzed. Next, a formula was constructed to implement the contrast of the heat transfer capacity between the axial and radial directions of bearing rings, and then a novel radial thermal equivalent resistance was proposed to represent the heat conduction capacity of bearing rings. We accordingly optimized the bearing node setting scheme to develop an efficient semi-empirical thermal grid for high-speed angular contact ball bearings, in which the oil-air separation and gray-box theory was also introduced to describe the heat convection in bearing cavities. Finally the improved thermal network for a motored spindle was planned to verify the above-proposed work, and the simulation results based on the current thermal models of bearings were also obtained and contrasted with the experimental values. For a further validation, the polynomial interpolation on test data, meanwhile, was performed to observe the temperature variation trend. The result of comparative analysis indicates that we show a more proper thermal assessment on bearing temperature.

Grain-size adjustment in Hf0.5Zr0.5O2 ferroelectric film to improve the switching time in Hf0.5Zr0.5O2-based ferroelectric capacitor

By adjusting the rising time in annealing ferroelectric HfO2-based films, the grain size of the film can be controlled. In this study, we found that increasing the rising time from 10 to 30 s at an annealing temperature of 700 °C in N2 atmosphere resulted in improved ferroelectric switching speed. This is because the larger grain size reduces the internal resistance components, such as the grain bulk resistance and grain boundary resistance, of the HZO film. This in turn lowers the overall equivalent resistance. By minimizing the RC time constants, increasing the grain size plays a key role in improving the polarization switching speed of ferroelectric films.

The multi-variable stepwise algorithm for internal short circuit detection in a serial battery pack with inconsistent state of health

Internal short circuit of cells is one of the main causes of thermal runaway in electric vehicle battery systems. Therefore, one of the most effective ways to prevent thermal runaway is to detect and identify internal short-circuit lithium-ion batteries before thermal runaway using a battery management system. This paper investigates the detection and identification of internal short circuits in batteries by proposing a multi-variable stepwise analysis (MSA) method. The MSA method is proposed for detecting and identifying faulty batteries by combining horizontal and vertical comparison methods and aging cells' ohmic internal resistance variation characteristics. A less consistent pack containing aging cells was designed to perform internal short-circuit experiments. Based on setting the appropriate threshold and moving the window frame horizontally, comparing the deviation degree of the ohmic internal resistance of each cell in the battery pack and the average ohmic internal resistance of the normal battery, the aging battery in the battery pack can be effectively identified. State of health (SOH) is the percentage remaining of the battery's actual maximum capacity value. The deviation degree of ohmic internal resistance of aging batteries with SOH of 92% and 80% is maintained at more than 15% and 45%. For early internal shorts with an equivalent internal short-circuit resistance of 100 Ω, the internal short-circuit detection time is 3896 s. For the short circuit in the middle and later periods (<10Ω), the MSA algorithm can achieve rapid internal short-circuit detection within the 50 s window, reducing the risk of thermal runaway. The results verified that the method could effectively identify aging cells within the battery pack and detect internal short circuits for other cells, reducing false positives and effectively preventing thermal runaway.

Ceramic matrix composite based on silicon carbide and nanostructured nitrogen-doped carbon for supercapacitor electrodes

The results of studies on the production of a porous ceramic-matrix composite material C–N/SiC from silicon carbide and nitrogen-doped nanostructured carbon for subsequent use as supercapacitor electrodes are presented. The material is formed by pressing silicon carbide micropowder (1 µm) and impregnating with a solution of carbamide (nitrogen source) in phenol-formaldehyde varnish (carbon source), curing and pyrolysis in a nitrogen atmosphere. The maximum concentration of carbamide was obtained in the solution (16 wt.%) at 50 ºС with a viscosity of 134.3 mPa⋅s. Thermogravimetric analysis in nitrogen of the cured solution revealed multistage decomposition with a residual mass of C–N of 48 % at 1000 ºС. Studies of the elemental composition showed a nitrogen content of 1.4 wt.% in C–N/SiC composite (up to 7 % of C–N active mass). In the composite structure, the C–N carbon-nitrogen layer (up to 12 wt.%) distributed inside the matrix pores and covering the SiC grains is X-ray amorphous has a complex nanoscale relief with an average pore size of 1.0–1.5 nm. According to electrochemical studies, the specific capacitance of the C–N/SiC material and the C–N active layer is 16.84 and 153.2 F/g respectively, and the equivalent resistance of the test supercapacitor cell with C–N/SiC electrodes is 0.567 Ohm for samples with maximum doping. The electrodes operate according to the sorption-desorption mechanism of charge accumulation and release, which is typical for a classic supercapacitor based on a double electric layer without the presence of redox reactions on the electrodes. The influence of technological regimes of pyrolysis on the electrophysical parameters of the cell is revealed: lower values of the pyrolysis temperature and nitrogen pressure in the chamber lead to an increase of the material specific capacitance and reduction of the cell equivalent resistance. The obtained results demonstrate the possibility of utilizing C–N/SiC material for the manufacture of supercapacitor electrodes.

A productivity equation of horizontal wells in the bottom water drive reservoir with an interlayer

The interlayer can effectively prevent the ridge of bottom water and has a non-negligible influence on the flow dynamics of oil and gas in the reservoir. In view of the above problems, this paper studies the influence of a bottom water reservoir with an interlayer on the critical productivity of horizontal wells and establishes a coupling model of seepage and wellbore flow in a bottom water reservoir with an interlayer. The critical productivity of horizontal wells in a bottom water reservoir with an interlayer can be evaluated more accurately. Firstly, the three-dimensional seepage field is approximately decomposed into internal and external seepage fields, and the critical productivity formulas of internal and external seepage fields are solved, respectively. Using the equivalent seepage resistance, the critical productivity formula of horizontal wells in interlayer bottom water reservoirs is obtained. The results are compared with the calculation results of the traditional productivity formula and the simulation results of the commercial software ECLIPSE. Second, based on the mass conservation principle and momentum conservation principle, the wellbore-reservoir coupling mathematical model of a horizontal well is established by the discrete method. Finally, the sensitivity analysis of the selected parameters is discussed in detail. The results show that: (1) compared with the traditional productivity algorithm, the algorithm considers the influence of interlayers on productivity and gives a detailed theory, a specific calculation process, and the importance of accurate prediction of wellbore flow. (2) The model is calculated by an example, and the calculation results are compared with the traditional formula and the commercial simulator ECLIPSE. The results show that the horizontal well productivity formula considering the influence of interlayer is closer to the simulation results of commercial software ECLIPSE, and the relative error is 8.56%. (3) The established coupling model considers the influence of interlayer radius length and horizontal well length. The general trend is that productivity gradually increases with an increase in interlayer radius length or horizontal well length, but the growth rate gradually decreases.