Liquid Level Changes Research Articles

LiqD: Dynamic Liquid Level Detection under Containers

Abstract. In daily life and industrial production, it is crucial to accurately detect changes in liquid level in containers. Traditional contact measurement methods have some limitations, while emerging non-contact image processing technology shows good application prospects. This paper proposes a container dynamic liquid level detection model based on U-Net. This model uses the SAM model to generate an initial data set, and then evaluates and filters out high-quality pseudo-label images through the semi-supervised framework to build an exclusive data set. The model uses U-Net to extract masking images of containers from the data set, and uses morphological processing to compensate for masking defects. Subsequently, the model calculates the grayscale difference between adjacent video frame images at the same position, segments the liquid level change area by setting a difference threshold, and finally uses a lightweight neural network to classify the liquid level state and achieves the accuracy of 91.39%. This approach not only mitigates the impact of intricate surroundings, but also reduces the demand for training data, showing strong robustness and versatility. A large number of experimental results show that the proposed model can effectively detect the dynamic liquid level changes of the liquid in the container, providing a novel and efficient solution for related fields.

Remote liquid level monitoring based on coda wave interferometry

Abstract Accurate monitoring of liquid level is important for both liquid stocking and related industrial procedures, it is however difficult under extreme circumstances where the inner space of the container is inaccessible or out of reach. Therefore, this paper proposes a remote liquid level monitoring method based on the use of ultrasonic coda wave interferometry. Coda waves stem from multiply scattering of elastic waves under the interactions with the boundary of propagation medium or scatters during their propagation, they are commonly observed in complex propagation medium. For having propagation trajectories much longer than the coherent waves, coda waves are capable of sampling the propagation medium repeatedly and more comprehensively, which in turn provides coda waves with higher sensitivity to its propagation medium. Letting ultrasonic waves propagate within the liquid container, which is often elastic medium, they are capable of probing the solid-liquid interface globally and repeatedly. As the changing in liquid level alters such solid-liquid interfaces inevitably, the propagation of coda wave is thus affected even without any contact with the liquid level. In this manuscript, experimental study is represented, of which the results show that waveform distortion of coda waves, estimated by remnant decorrelation coefficients, is quantitatively related with the change of liquid level, demonstrates the feasibility of remote liquid level measurement and continuous monitoring of liquid level with ultrasonic techniques.

Torque measurement during stirring process research on the pilot plant

This article deals with the torque measurement mechanism of the mechanical stirring process. The resulting shear stresses or strains measure the torque. The authors provide a torque meter classification and various methods of torque measurement to accurately measure and control torque. They are important parameters in the design and manufacture of various devices and mechanisms. The paper presents a schematic diagram of a pilot plant to investigate mechanical stirring using the developed torque measurement device without the use of a stroboscope. The method proposed by the authors solves the problem related to simplification of technical torque measurement. The authors calculated the range of liquid level change in the piezometer during the study of the stirring process at the pilot plant, taking into account the minimum and maximum values of pressure in the vessel.

Ultrasonic liquid level detection method based on the variation of reflected energy on the inner wall of a container

Liquid level detection plays an important role in industry. For the liquid level detection of flammable, explosive and volatile liquids, the detection method based on the ultrasonic principle is usually adopted. Though a lot of efforts, the detection precision is still challenging. Herein, Ultrasonic liquid level detection method is studied to address the detection precision. A projection model of the inner wall of the sound beam is established. The transmitter–receiver probe is placed near the height of the liquid level on the outer wall of the liquid tank. The sound beam emitted by the probe passes through the tank wall and generates a projection area on its inner wall. The energy of the echo signal received by the probe is calculated, and the relationship between the proportion of liquid in the projection area and the energy is used to detect changes in the liquid level. The test system is set up, the echo signal received by the probe is collected, and its normalized energy is calculated. The results show that for different tank wall thicknesses, liquid types and detection frequencies, the normalized energy can clearly characterize the change of liquid level with an error of less than 3 mm. It provides a new avenue for liquid level detection. The research also shows that for the determined detection frequency, when the tank wall thickness corresponds to the values greater than or equal to the critical distance of the probe, the detection accuracy of liquid level change is the highest.

Uncertainty propagation in the simulation of a nuclear power plant operational transient

With the continuous deployment of various intermittent energy sources on the grid there is an increasing opportunity for nuclear reactors to perform power maneuvers which can help alleviate issues related to supply oscillations during some periods of high renewable output. While utility specific codes can model such transients for safety assessments, there is a need to increase confidence in the application of these codes and to quantify the capabilities and accuracies of models in predicting these transients. In this work a power maneuver from 100 % full power to 59 % full power for a large CANDU reactor was studied using the TRACE-PARCS toolset. The work was computationally expensive as it examined both the effects of i) nuclear data library uncertainty which requires re-generation of the few-group cross sections and regeneration of an equilibrium core using 4 years of synthetic fuelling, and ii) initial core burn-up distribution involving the simulation of online fuelling operations over a period of 1400 days.The figures of merit considered in this work include changes in the average liquid zone controller fill level, individual channel powers, and the timing of adjuster bank withdrawals and reinsertions. Amongst the 100 s of simulated transients, the average time between adjuster bank withdrawals to override the Xenon transient and absolute standard deviations in these timings were found to be consistent between different nuclear datasets. The observed standard deviations were small, suggesting that the sensitivity to both nuclear data and initial core configuration is relatively small for both the adjuster withdrawal phase and the reinsertion phase. The contributions to total uncertainty due to both the core initial conditions and the nuclear data uncertainty were determined. During the early phase of the transient (i.e., adjuster withdrawals) nuclear data uncertainty and initial condition uncertainties were found to contribute nearly equally to total uncertainty, with slightly larger contributions due to nuclear data uncertainty. For adjuster bank reinsertions later in the transient it was observed that the contribution to total uncertainty by initial condition uncertainty was on average twice that of nuclear data uncertainties.The transients were compared to an actual power maneuver in a ∼900 MW CANDU reactor. In all cases, the model’s behaviour, while qualitatively correct, systematically over-predicted the time durations between adjuster movements and this difference exceeded the envelope of simulations that account for nuclear data and initial core configuration. Sensitivity studies performed to investigate the discrepancies suggest that additional refinements to the RRS emulator used in this work are required to match the station RRS more closely and that the transient evolution is highly sensitive to the initial excess reactivity in the core, which was observed to be lower in the station than in the TRACE simulations. Based on the simulation results the combined impact of the emulator responses, initial average zone levels, and incrementals modelling have a larger uncertainty than those related to nuclear data and initial core burnup distribution.

New Developments in Detector and Bund Wall Standards to Mitigate the Risk of Hazardous Liquid Leaks

Ensuring early leak detection and implementing effective secondary containment systems are critical for preventing the dispersion of hazardous liquids and minimizing the casualties of a chemical accident. This study reviews the standards for leak detectors and their placement in various regions, as well as the key parameters involved in bund design such as bund capacity, bund wall height, and separation distance from the bund wall. In this study, Computational Fluid Dynamics (CFD) simulations are conducted considering storage tanks with heights (H) of 1.75 m, 3.5 m, and 7.0 m. The detection times using a level transmitter (LT) and a leak sensor are compared at eight monitoring points. Exclusively employing the leak sensor led to a significant detection time delay of up to 16 times, ranging from 0.5 s to 8.1 s depending on the placement of the leak sensors. However, the average rate of liquid level change was 3.0 mm/s, which demonstrates that the LT consistently detects leaks faster than the leak sensor at all monitoring points. Hence, the integration of an LT alongside a leak detector offers a valuable approach to expedite leak detection, regardless of the direction or location of the leak. Furthermore, the optimized separation distance between the storage tank and the bund wall is suggested. The analytical solution and numerical solution for a separation distance matches up to 95% for H=1.75 m. The separation distance increases as both the tank height and the height of the leak source increase. The relationship between the separation distance and the tank height exhibits a square root dependence on the liquid level from the leak point. The proposed detection method and optimized separation distance hold the potential to facilitate a revision of liquid storage and handling standards grounded in robust scientific and quantitative evidence.

Dynamic liquid level prediction in oil wells during oil extraction based on WOA-AM-LSTM-ANN model using dynamic and static information

Accurately predicting the dynamic liquid level is the key to energy efficient operation of oil wells, however, the dynamic liquid level of oil wells in the same area varies widely, and the existing methods cannot achieve uniform modeling of the dynamic liquid level of multiple wells with high accuracy. To this end, based on the parameters of the multi-wells production process, this paper proposes method for predicting the dynamic liquid level of oil wells based on a Long short-term memory (LSTM) with attention mechanism (AM) and artificial neural network (ANN) optimized by the whale optimization algorithm (WOA). First, the factors significantly related to the change in the dynamic liquid level are identified and divided into dynamic and static information. Dynamic features are extracted using AM-LSTM. AM can enhance the impact of important information when extracting dynamic features using LSTM; Static features are extracted through ANN; Finally, both dynamic and static features are used as inputs to ANN to predict the dynamic liquid level. Solve the prediction model parameter selection problem with WOA. Using historical oilfield data collected in the field for validation, the experiment proves that the proposed method in this paper is effective for predicting the dynamic liquid level of multi-wells. Therefore, this prediction model can be used as a tool to detect the dynamic liquid level, which can achieve the purpose of reducing energy consumption and improving efficiency during oil extraction.

Liquid-level measurement based on out-of-plane energy of Lamb waves

The accurate detection of liquid-level plays an important role in industrial process. This paper presents a method for liquid-level measurement based on Lamb waves. The dispersion equation of Lamb waves under unilateral liquid load is deduced to obtain the dispersion curves. The structure and attenuation curves are analyzed under a certain frequency and thickness, and the modes with more energy loss are selected. The ratio of the signal energy of the liquid-level at the upper and lower positions is defined as the discrimination to indicate the change of the liquid-level. The models of the liquid storage tank are built and the Lamb waves of different modes are simulated using the finite element method. The experimental results reveal that it is easy to detect the difference in ultrasonic signals when the liquid-level changes. Compared with the longitudinal wave detection method, the proposed method improves the discrimination of liquid-level detection. The experimental results are consistent with the theoretical calculations.

THE USE OF VAPOR RECOVERY UNIT (VRU) TO COVER EVAPORATON LOSS OH CONDENSATE TANK Y AND Z AT PT SHI PRABUMULIH

Crude oil is a mixture of hydrocarbon and non hydrocarbon in liquidp phase on earth. crude oil is not ready to use fuel or any other engery source. it needs to be processed through refining unit to be fuel. In the prosess of receving stockpiling and distribution of oil quantity loss can occur called losses. One of them is evaporation loss caused by evaporation that triggers of product loss. Fluid tend to evaporate according to its vapor pressure. The amount of evaporation loss occurred in condensate tank of Y and Z at PPP of PT SHI was rather high. The evaporation loss on tank type fixed cone roof tank was divided into breathing loss and working loss. Breathing loss refersh depreciation at night because of the environment temperatur. Meanwhile, working loss refers to losses of condensate product from liquid level change caused by receiving and distribusting activities. In this research, the author analyzed a new innovation to avoid evaporation loss on crude oi tank of condensate type using an effective and economic method. The company could apply vapor recovery unit using activated carbon system on condensate tank Y and Z. The economic research indicated that the profit was IDR 2.3 Billion and the investment cost was IDR 720.7 Million.

Portable Multihole Plastic Optical Fiber Sensor for Liquid-Level and Refractive Index Monitoring

In this article, we report a low-cost method to fabricate plastic optical fiber (POF) liquid-level and refractive index (RI) sensors integrated with smartphones by molds and drilling microholes in side-growing POFs (SGPOFs) with high-temperature metal wire. These sensors can be used for real-time liquid-level and RI monitoring, especially under situations requiring portability and illumination. When the liquid level changes, the change of the RI around the microholes leads to a change in the light intensity transmitted in the fiber, enabling us to measure the liquid level and RI. Utilizing one sensor with six holes (0.45 mm radius and 15 mm spacing) in 2.0-mm SGPOF, the results of level and RI measuring are in good agreement with the theory. The liquid-level measurement of the sensor is carried out for water with an RI of 1.333, the level sensitivity is 0.29%/cm ± 0.02%/cm. In the RI measurement, the RI sensitivity of the sensor is −22.8%/RIU ± 0.6%/RIU in the measurement range from 1.333 to 1.475.

Real-Time Identification and Positioning of Sewer Blockage Based on Liquid Level Analysis in Rural Area

Sewer blockages delay sewage discharge or cause it to overflow, which pollutes the environment and is a public health hazard. This necessitates the quick and accurate identification and positioning of sewer blockages. Following a sewer blockage, the sewage is intercepted and the liquid level at the upstream and downstream of the blocking point changes. This study established a method for identifying sewer blockages by analyzing the range and rate of the liquid level change at the upstream and downstream of the blocking point. Through pilot-scale and full-scale experiments, this study summarized the threshold values of the liquid level change rate and the liquid level fluctuation range of the drainage pipeline in normal operation, as well as the threshold values of the liquid level change rate and the liquid level fluctuation range of the upstream and downstream of the sewer blocking point. Moreover, the sewer blockage identification matrix was completed. Sewer blockage in rural areas can be identified and positioned using mathematical tools such as the data-driven model. This research method allows for real-time monitoring and timely warning of the sewer status, thereby reducing the labor and material consumption and unnecessary earthwork excavation to ensure the stable operation of the drainage pipeline.

High-Sensitivity Liquid Level Sensor Based on the Balloon-Shaped Fiber Optic MZI

We demonstrated a high-sensitivity liquid level sensor based on the balloon-shaped fiber Mach-Zehnder interferometer (MZI). To make an optical fiber MZI sensor, a bare single mode fiber (SMF) is bent into a balloon shape. The sensor is attached to a stiff support and linked to a buoyancy ball floating on the liquid surface via a thin thread. The change in liquid level will bend the fiber and lead to a wavelength shift of transmission spectrum. This is a novel method of measuring liquid levels. We comprehensively studied the sensing performance of the sensor, and applied the ridge regression algorithm to optimize the fitting results of the experimental data. The maximum sensitivity of liquid level and temperature are 5.245 nm/mm and 40.3 pm/°C respectively, and the sensor has a low temperature cross-sensitivity of 0.00768 mm/°C. Furthermore, the sensor has the advantages of real-time response, convenient manufacture, low cost and high reliability, which broadens the application area of balloon-shaped MZI and makes it appropriate for liquid level sensing.

Anomaly Detection and Analysis Based on Deep Autoencoder for the Storage Tank Liquid Level of Oil Depot

In the industrial control system of oil depot, the change of storage tank liquid level is closely related to the transportation process and site management of oil depot. It is of great significance to detect the abnormality of storage tank liquid level data for the safe and stable production of oil depot. A data-driven anomaly detection strategy is proposed by analyzing the non-periodic time series data of the oil storage tank liquid level. Based on the convolutional autoencoder algorithm to learn the features and patterns of a large number of samples, the strategy is carried out by reconstructing the samples and calculating the reconstruction error, which not only does not rely on the labeled samples, but also improves the detection precision. This paper chooses three algorithms of convolutional autoencoder, RNN (Recurrent Neural Network) autoencoder and LSTM (Long Short-Term memory) autoencoder for experimental analysis. Experiments were carried out on the oil tank historical data set and NAB (Numenta Anomaly Benchmark) simulation data set respectively. The results show that the accuracy of convolutional autoencoder is 98% and the F1 score is 82%, which is more practical for the scenes with real-time requirements.

Compact Multifunctional Five-Wire Line-Based Microwave Sensor for Volumetric Characterization of Liquids

A new microwave sensor system with a five-wire line configuration is developed for volumetric characterization of liquids. Compared with the existing permittivity-based evaluation methods, the sensor is low profile, low-cost, submersible, easy to fabricate and implement (can be inserted into a container through a small access). An analytical model is proposed for accurate permittivity determination, and the effects of the line length and frequency range on the signals are thoroughly studied for optimal setting. The accuracy of the sensor is verified with standard liquids of known permittivity. From the measurement of honey and alcoholic drinks, explicit relationships are found between the permittivity and the constituent content, thereby facilitating liquid discrimination. The potential for the detection of liquid stacking and level change is well demonstrated in the evaluation of oil samples. The sensor offers an alternative solution to assessment of a wide range of liquids in food, oil, agricultural and bio-sensing applications.

Dynamic response of gravity-driven flow in multi-section absorption heat pump

The multi-section absorption heat pump (AHP) is applied in the novel district heating (DH) system of China. This new type of AHP exhibits improved performance in DH systems, but involves a more complicated structural design and the risk of internal flow instability problems such as reversed pressure difference and liquid accumulation. The flow circulations of the solution and refrigerant consist of several gravity-driven flow processes that are rarely observed in conventional AHPs, and these processes have not been addressed in previous studies. The present work studies the dynamic response of gravity-driven flow inside a multi-section AHP in a DH system. A dynamic model capable of calculating the liquid level, flow rate, and pressure change of various gravity-driven flow processes is developed and validated. The steady-state conditions calculated by the dynamic model are compared with a validated model in the literature. The gap between the temperature and pressure calculations is less than 0.3 K and 0.05 kPa, respectively. The dynamic simulation results are compared with the start-up process test results of a multi-section AHP. The pressure values and trend change fit the test results well. The standard deviation (SD) and root-mean-square error (RMSE) of the pressure calculation errors are less than 5% and 5.5%, respectively. The model is used to study typical transient processes of multi-section AHPs in a DH system. In the start-up process, the pressure of the generator is 1–2 kPa lower than that of the absorber after the solution circulation begins. This reversed pressure difference leads to solution accumulation at the bottom of the generator. The solution flow rate into the absorber is 20% lower than the designed value. After the heat source is input into the generator, the reversed pressure difference disappears. Solution accumulation expedites the flow of the solution into the absorber. The flow rate is 75% higher than that of the designed value, leading to solution accumulation in the absorber. In the heat source sudden drop process, reversed pressure difference and solution accumulation problems also occur. The reasons for flow instability in each process and possible methods for preventing them are discussed.

Defrosting dynamic behaviors of a propane air conditioner and its rotary compressor under low ambient temperature conditions

Due to the great potential of propane in environmental protection and thermodynamic properties, the promotion of propane room air conditioner will make a great contribution to environmental protection. The defrosting behaviors of propane room air conditioner system and rotary compressor were studied by experiments in this paper. Experimental analysis redefines and distinguishes defrosting time and frost melting time, and their relationship with condition temperature is different. The experimental results show that the lower the ambient temperature was, the longer the defrosting time was, but the shorter the frost melting time on the outdoor heat exchanger was. The state of the oil sump and foam layer in propane rotary compressor using Mineral Oil (MO) was recorded and the variation reason for liquid level was analysed during defrosting. Combined with the change of viscosity and liquid level of the oil sump, the experimental results show that the compressor has abnormal oil discharged, and the lower the ambient temperature was, the larger the oil discharge was under three conditions during defrosting process. The total mass of the mixture in the oil sump under the three working conditions is 275.18 g, 289.10 g and 276.41 g, the lubricating oil is 202.97 g, 200.23 g and 189.71 g, and the refrigerant mass is 72.21 g, 88.87 g and 86.71 g respectively when the defrosting process ended. This study will provide an experimental basis of the reliability study and application of propane air conditioners.

Theoretical Derivation and Experimental Study of Liquid Equilibrium Shapes under Different Rotation Modes.

Research shows that the surface shape of rotary liquid depends on the rotation mode. Mode A is that when the container wall rotates the liquid, the rotating liquid surface is paraboloid. Mode B is that when the rotor in the center of the container rotates the liquid, the rotating liquid surface is vortex. Based on the paraboloid formed by the mode A, the identity between the liquid level parameter and the wall slope K (K ≠ 0) is derived. When K → ∞, with the increase of the container angular spin rate, the liquid level parameter changes are infinite, the liquid level change and volume relationship are fixed. When K > 0, the container is a cylinder with a large upper part and a small lower part and the liquid level parameter changes are limited, and the limit ratio between the liquid level parameters is + 1. In addition, through the vortex experiment by the mode B, it is concluded that the vortex curve can be regarded as composed of three parabolas: the center triggering part, the rising part, and the edge attenuation part. Different from the mode A, the liquid level change and volume relationship caused by the vortex formed by the mode B are both variables. According to the experimental results, the influences of container inner diameter, initial liquid level, rotor size, and rotor speed on the vortex characteristics are discussed in detail. At the same time, based on the experiment, the liquid level change and volume relationship caused by the formation of the vortex are deduced under the ideal condition when a stable liquid surface is formed by the vortex.

An inline Mach-Zehnder interferometer for simultaneously measuring liquid level and temperature

A compact optical fiber sensor (OFS) based on an inline Mach-Zehnder interferometer for simultaneousmeasurement of liquid level and the temperature isproposedanddemonstrated experimentally. The proposed sensor is formed by fusion splicing a thin core fiber (TCF) with an ultra-thin fiber (UTF) with core offset, then TCF and UTF are sandwiched between two standards of single mode fibers (SMFs). The liquid level or temperature change will lead to the dips shifts in the interference spectrum, and the liquid level and temperature sensitivities can be measured independently by monitoring the resonance dips shifts. Then the simultaneous measurement of liquid level and temperature can be obtained through the demodulation matrix. Four sensors with different UTF length are fabricated based on numerical simulation. The experimental results show that the proposed sensor with a UTF length of 8 mm has the optimal liquid level and temperature sensitivities of −231.67 pm/mm and 77.86 pm/°C, respectively. The measuring liquid level and temperature ranges are 0–8 mm and 30–60 °C. The proposed sensing configuration has practical application potential in various industries due to the advantages of high sensitivity, simple fabrication and low cost.

Simultaneous Measurement of Liquid Level and Temperature Using In-Fiber Grating-Based Mach-Zehnder Interferometer and Faraday Rotator Mirror.

Here we propose an optical fiber sensor capable of simultaneous measurement of liquid level and temperature by utilizing cascaded long-period fiber gratings (LPFGs) inscribed on high-birefringence fiber (HBF) and a Faraday rotator mirror (FRM). Due to the in-fiber Mach-Zehnder interference and birefringence of the HBF, these cascaded LPFGs have polarization-dependent discrete interference spectra, each of which is created within one of the two different attenuation bands obtained in the two orthogonal input polarization states, e.g., linear horizontal polarization (LHP) and linear vertical polarization (LVP). The minimum transmittance dip was selected as a sensor indicator for each interference spectrum obtained for LHP or LVP input signal. To monitor these indicator dips associated with LHP and LVP, referred to as the IDH and IDV, respectively, with one spectral scanning, an FRM was connected to the end of the cascaded LPFGs. Both the IDH and IDV spectrally shifted according to liquid-level or temperature changes and showed very linear responses to them with adjusted R₂ values greater than 0.997. The liquid-level sensitivities of the IDH and IDV were measured as approximately -37.29 and -121.08 pm/mm in a liquid-level range of 0 to 55 mm, respectively. The temperature sensitivities of the IDH and IDV were measured as ˜28.79 and ˜218.21 pm/°C in a temperature range of 30 to 60 °C, respectively. Owing to their linear and independent responses to liquid level and temperature, our sensor can perform temperature-independent liquid-level measurement using their pre-determined liquid-level and temperature sensitivities, even if both liquid level and temperature change simultaneously.

Low Refractive-Index and Temperature Crosstalk Fiber-Optic Liquid Level Sensor Based on Cascaded Quasi-Microfiber and Double-Cladding Fiber Structure

In this paper, a novel in-fiber modal interferometer for liquid level sensing is proposed and experimentally demonstrated based on the cascaded quasi-microfiber and double-cladding fiber (QM-DCF) structure. The QM is utilized to monitor the change of liquid level with intensity modulation and the part of DCF is always immersed into the liquid and serves to sense the variation of ambient temperature. Then the comprehensive tests are performed and the experimental results show that, due to the massive loss of evanescent field in the area of taper waist, a competitive liquid-level response up to -0.972 dB/mm with high linearity is gained and the calculated detection limit reaches ~ 10μm. Moreover, this cascaded structure is almost immune to the varied refractive index (RI) of liquid especially in the range of 1.33-1.357 RIU and its temperature sensitivity is 0.164 nm/°C but with a fluctuation of <; 0.1 dB. Thus, high intensity-sensitive liquid-level measurement is achieved with near-zero crosstalk in terms of RI and temperature. Besides our sensor with the merits of practicality, low-cost, ease of fabrication is very promising and potential for simultaneous high-discrimination measurement of multi-parameter.