Temperature Monitoring Points Research Articles

Analysis and Experiment on the Welding Temperature Field of Multi-Layer and Multi-Pass for RHS–RHS Y-Connections

The temperature measuring instrument was utilized to monitor the welding temperature field at designated points along steel rectangular hollow sections (RHSs) during welding. A total of 32 temperature monitoring points were established on the four surfaces of the RHS branch. Additionally, the welding process was simulated using finite element software to calculate the temperature distribution. The calculated temperature results were then compared with the experimental results obtained from the temperature measuring instrument. The relative errors between the numerical simulation and the experimental temperature results remained within 10%, indicating a reasonable agreement between the two. Once the temperature field was determined, it was used as an input load to calculate the welding residual stress. The longitudinal and transverse residual stresses were analyzed for two paths on the four surfaces of the RHS-to-RHS Y-shaped connection branch. By analyzing the residual stresses, it is possible to evaluate the structural integrity and performance of the welded RHS connection. The analysis process in this paper is crucial for ensuring the safety and reliability of tubular steel structure projects.

A causal prediction model for the measured temperature field of high arch dams with dual simulation of lag influencing mechanism

Mathematical models using measured dam temperature as modelling factors are frequently used in displacement-based structural health monitoring of high arch dams. However, when these models are used to predict future displacement, dam temperature is also unknown, thus it is necessary to predict the temperature field of the dam body in the first step. The main purpose of this paper is to improve the accuracy and rationality of data-driven models in simulating the complex lag influencing mechanism of temperature field in high arch dams. Two strategies are integrated from the perspective of modelling factors and modelling methods. First, based on massive temperature monitoring data, lag influencing times and laws of air temperature and upstream reservoir water level on dam temperature are quantified using cosine similarity and Shapley additive explanation. Based on the main influencing factors and the optimal lag time, dam temperature field zoning and modelling factor optimization methods are proposed. On this basis, a causal prediction model is established for the measured temperature field of high arch dams using the nonlinear autoregressive with exogenous inputs (NARX) neural network, by which the lag influencing mechanism preliminarily simulated through modelling factors can be further optimized. The results of the Jinping-I arch dam indicate that the causal mechanism of arch dam temperature field is nonlinear and hysteresis. The proposed method has achieved the quantification standards of temperature field zoning and modelling factor optimization for high arch dams based on the lag influencing mechanism, and the obtained temperature field zones of the dam body are consistent with the actual situation. Compared with the frequently used support vector machine model, the NARX model can significantly improve the prediction accuracy of dam temperature field, where the root mean square error of all 134 temperature monitoring points on the dam body decreases with an average rate of 76%.

Anti-Condensation Temperature Control Strategy of the Concrete Radiant Roof

Radiation cooling, as a new terminal mode that has been gradually emerging in recent years, has attracted more and more attention. However, the problem of condensation has become a vital bottleneck restricting the broad application of radiation-cooling technology. This paper used the numerical simulation method of Ansys Fluent to study the effect of different water supply parameters on the concrete radiant roof’s heat transfer performance, temperature uniformity analysis, and anti-condensation temperature control strategy. The accuracy of the simulation model was verified by comparing the numerical simulation values and measured values of temperature monitoring points. In thermal performance research, the inlet temperature significantly impacted the cooling capacity and radiant surface temperature compared with the inlet flow velocity. In the uniformity study, the distance between the serpentine pipes area and the concrete edge was easily neglected, which was also an important factor affecting the distribution of temperature uniformity. Regarding anti-condensation and performance improvement research, first supplying water at low temperatures and then dynamically adjusting high-temperature water could effectively avoid condensation and improve the radiant roof’s heat transfer performance. The research results could provide technical references for the practical application of radiation roof anti-condensation temperature control technology.

Thermal Conduction Heating for a 125 ft Deep TCE Source—Multiple Lines of Evidence for Verification of Remedial Goals

AbstractThis paper describes thermal conduction heating of a trichloroethylene (TCE) source zone within vadose zone soils consisting of glacial till at depths of 50 to 125 ft below an active manufacturing facility. The performance objectives and metrics used to determine remediation success are presented. Access limitations inside the facility prevented traditional spatial soil confirmation sampling, which made performance assessment a unique challenge. Instead, the project team developed an approach utilizing multiple lines of evidence to document remedy completeness. These lines of evidence included achievement of target temperatures within the treatment volume, demonstration of asymptotic vapor concentrations extracted from the treatment volume, achieving modeled energy input goals, and verifying TCE concentrations in post‐treatment soil samples collected at the few accessible locations within the operational facility. The treatment volume was divided into three discrete treatment areas or heating groups, each constructed and heated independently in order to meet an aggressive project schedule. Additionally, each line of evidence was required to be met in each group. After approximately 283 days of heating, temperatures exceeded 90 °C at 95% of the temperature monitoring points, TCE levels had diminished to asymptotic levels in the recovered vapors, and mass removal rates from the treatment volume declined to minimal levels. Confirmatory soil sample results indicated that average TCE concentrations achieved were more than an order of magnitude below the remedial goal of 1 mg/kg.

A 3-D thermal network model for the temperature monitoring of thermal grease as interface material

In the cooling system of insulated gate bipolar transistor (IGBT) module, the reliability of thermal grease is of crucial importance in the heat dissipation of IGBT module. In order to study the influence of thermal grease, thermal interface material (TIM) between IGBT module and heat sink, on the junction temperature of IGBT module under long-term load profiles, a 3-D thermal network based on thermal grease temperature monitoring is proposed. Firstly, the finite element method (FEM) simulation model of IGBT module using thermal grease as TIM is established. Then, considering thermal coupling effect, the temperature distribution of thermal grease is obtained and the temperature monitoring points of thermal grease are determined in FEM simulation. Finally, a 3-D thermal network is established to monitor the temperature in all regions of thermal grease. The influence of thermal grease degradation on the junction temperature of IGBT module is analyzed and the temperature distribution of thermal grease under long-term load profiles is obtained. The proposed 3-D thermal network model based on the temperature monitoring of thermal grease can increase the accuracy of IGBT module reliability analysis.

Simulation Analysis and Experimental Research on Complex Structure Processing Technology of Fan Vent

Aiming at the problems of large temperature differences and inconsistent baking speeds at different positions in the tobacco chamber of the tobacco baking room, this paper proposes a complex structure processing technology of fan vent. according to the structure and drying principle of the baking room, ANSYS fluent simulation software was used to analyze the processing parameters of the heat flow field inside the baking room. combining the characteristics of positive and negative air supply baking, the processing and manufacturing parameters of the baking room were optimized, and then the baking comparison test was performed. The results show that: the forward and reverse air-baking method and the complex structure reduces the temperature difference in the interior of the smoke chamber; the forward and reverse air-bake method reduces the baking time by 11 hours, and reduces the coal consumption and power consumption by 12.6%, 48.5%, the standard deviation of temperature monitoring points in the baking room decreased by 44%.

Thermofluidic modeling and temperature monitoring of Li-ion battery energy storage system

The battery energy storage system (BESS) is widely used in the power grid and renewable energy generation. With respect to a lithium-ion battery module of a practical BESS with the air-cooling thermal management system, a thermofluidic model is developed to investigate its thermal behavior. The thermal model for a single battery is established and experimentally validated first, and then the thermofluidic model for this battery module is developed based on the single battery thermal model and validated by experimental data also. Simulations are performed considering the practical frequency regulation condition and some hypothetical situations with unexpectedly high heat generation rates. Thermal behaviors of the battery module under different conditions are carefully analyzed. Results show that the fans-on forced air convection cooling reduces the maximum temperature by 0.4 K and makes the maximum temperature appear in a different battery of the BESS module compared with the natural air convection cooling. Especially, the temperature monitoring strategy is studied. Due to technical and cost constraints, only a limited number of temperature monitoring points can be set and the temperature that can be monitored is the battery surface temperature or some connecting bars’ surface temperature. The rationality of the locations of different temperature monitoring points is analyzed. The obtained results clearly indicate that enough caution must be paid when setting the temperature monitoring points in practical BESSs. The bad temperature-monitoring strategy may largely underestimate the maximum temperature (by as much as 3 K under the normal frequency regulation condition, and probably much larger under harsh working conditions) in the BESS and fails at reflecting the thermal status of the BESS.

Performance of Biodrying Process based on Temperature Profile and Cumulation

The biodrying process of solid waste is an approach to the use of biomass energy, where solid waste is dried using the heat generated from aerobic degradation of organic matter. Temperature profile and cumulation of the solid waste biodrying process are the success factors in drying solid waste. The reactor used is made of plywood with dimensions of (30 × 30 × 100) cm equipped with a heat sink using Thermoshield Universal to minimize heat loss. Aeration discharge at the biodrying process reactor is 0.023 m3/kg/h. The results showed a maximum temperature of 61°C produced from the bottom layer of the biodrying reactor (addition of 6 l / min air flow) on the first day at 10:00 pm. Cumulation temperature in the bottom layer of the biodrying reactor for 21 days of research reached 186.9°C. This value is a source of heat generated from the decomposition of waste under aerobic conditions. Based on the three layers, it can be concluded that the bottom layer produces higher temperature cumulation than the top or middle layer. This research can be a reference for determining temperature monitoring points and knowing Temperature cumulation generated from the waste decomposition process using biodrying technology.

Research on early-warning index of the spatial temperature field in concrete dams.

Warning indicators of the dam body’s temperature are required for the real-time monitoring of the service conditions of concrete dams to ensure safety and normal operations. Warnings theories are traditionally targeted at a single point which have limitations, and the scientific warning theories on global behavior of the temperature field are non-existent. In this paper, first, in 3D space, the behavior of temperature field has regional dissimilarity. Through the Ward spatial clustering method, the temperature field was divided into regions. Second, the degree of order and degree of disorder of the temperature monitoring points were defined by the probability method. Third, the weight values of monitoring points of each regions were explored via projection pursuit. Forth, a temperature entropy expression that can describe degree of order of the spatial temperature field in concrete dams was established. Fifth, the early-warning index of temperature entropy was set up according to the calculated sequential value of temperature entropy. Finally, project cases verified the feasibility of the proposed theories. The early-warning index of temperature entropy is conducive to the improvement of early-warning ability and safety management levels during the operation of high concrete dams.

SOFI/Substrate integrity testing for cryogenic propellant tanks at extreme thermal gradient conditions

Liquid propellant tank insulation for space flight requires low weight as well as high insulation factors. Use of Spray-On Foam Insulation (SOFI) is an accepted, cost effective technique for insulating a single wall cryogenic propellant tank and has been used extensively throughout the aerospace industry. Determining the bond integrity of the SOFI to the metallic substrate as well as its ability to withstand the in-service strains, both mechanical and thermal, is critical to the longevity of the insulation. This determination has previously been performed using highly volatile, explosive cryogens, which increases the test costs enormously, as well as greatly increasing the risk to both equipment and personnel.CTD has developed a new test system, based on a previous NASA test that simulates the mechanical and thermal strains associated with filling a large fuel tank with a cryogen. The test enables a relatively small SOFI/substrate sample to be monitored for any deformations, delaminations, or disjunctures during the cooling and mechanical straining process of the substrate, and enables the concurrent application of thermal and physical strains to two specimens at the same time. The thermal strains are applied by cooling the substrate to the desired cryogen temperature (from 4 K to 250 K) while maintaining the outside surface of the SOFI foam at ambient conditions.Multiple temperature monitoring points are exercised to ensure even cooling across the substrate, while at the same time, surface temperatures of the SOFI can be monitored to determine the heat flow. The system also allows for direct measurement of the strains in the substrate during the test.The test system as well as test data from testing at 20 K, for liquid Hydrogen simulation, will be discussed.

A Barn Temperature Prediction Method Based on MATLAB

In the Inner Mongolia beef cattle feeding, barn temperature is an important parameter. Barn temperature has an important impact on cattle breeding and beef production. In order to ensure that there is appropriate temperatures barn, data recorded in the barn a month temperature monitoring points, the acquisition time for each temperature monitoring point for the one-hour time interval. Using MATLAB software barn temperature data were analyzed, the data fit (least squares) and plotted, and finally get a barn temperature prediction formula. And use this formula to predict the temperature of the barn, forecasting results show that the design is reasonable, the error is small, can be applied in practice.

Numerical Simulation and Monitoring of Mass Concrete Wall Temperature Field

This paper investigated the calculation of mass concrete wall temperature field by ANSYS and compared the results with measured results, based on radiation protection mass concrete wall of medical linear accelerator in Wuhan Union Hospital.The solid70 was selected as the concrete element and reasonable boundary conditions and environmental conditions were set in the analysis of ANSYS.The results shows that temperature field distribution and development law obtained through numerical simulation analysis are consistent with measured results,which can help set up the temperature monitoring points.

Study on the pre-ignition characteristics of wire insulation in the narrow channel setup

A narrow channel setup was established and experiments were conducted to study the pre-ignition characteristics of wire insulation under overload conditions in weak buoyancy environment. The pre-ignition temperature variation trend of both the wire insulation and its nearby temperature monitoring points, the movement characteristics of smoke produced from the wire insulation and the ignition delay time of wire insulation were investigated. The results indicated that the narrow channel setup with a height of 10–15 mm was effective to suppress the effect of buoyancy, and the pre-ignition characteristics of wire insulation in microgravity could be predicted well by the narrow channel method.

VERTICAL LOADING OF TEMPERATURE CABLES

ABSTRACT One of the most popular methods of determining potential locations of spoilage in stored grains is through constant monitoring of the internal temperatures of the grain mass. Distinctive increases of the local temperatures in the grain are a good indication of potential spoilage problems. Daily inspection of the internal temperature of the stored grain can detect the presence of a hot spot before any grain is seriously deteriorated. The operator can then choose to aerate the grain to cool the hot spot or remove the grain from the bin. Daily monitoring of temperatures requires that sensing elements be placed within the grain mass. A common method of monitoring temperatures in a mass of stored grain utilizes thermocouples attached at regular intervals to high-strength steel cables. The entire assembly including the thermocouples and the cables is coated with a protective jacket. Temperature-sensing cables are available in many types, differing in surface material, size and cross-sectional shape. These cables are typically suspended from a grain bin roof in a standard pattern so they form a three-dimensional matrix of temperature monitoring points. Article was submitted for publication in January 1990; reviewed and approved for publication by the Structures and Environment Div. of ASAE in July 1990. Presented as ASAE Paper No. 89-4002. This work is published with the approval of the Director of the Kentucky Agricultural Experiment Station and designated as Paper No. 89-2-113. Major funding for the research reported in this article was provided by the Farm and Industrial Equipment Institute, Chicago, IL, and the University of Kentucky Agricultural Experiment Station. Part of the equipment used in this research was donated by Brock Mfg. Co., Inc., Milford, IN; Butler Mfg. Co., Kansas City, MO; Chief Industries, Inc., Grand Island, NE; Clayton & Lambert Mfg. Co., Buckner, KY; Floss Food Technology Corp., Eden Prairie, MN; and Mix-Mill Mfg. Co., Inc., Bluffton, IN. The authors are C. V. Schwab, Assistant Professor, Agricultural Engineering Dept., Iowa State University, Ames; R. A. Curtis, Research Assistant, Agricultural Engineering Dept., University of Kentucky, Lexington; S. A. Thompson, Associate Professor, Agricultural Engineering Dept., University of Georgia, Athens; and I. J. Ross, Professor and Chairman, Agricultural Engineering Dept, University of Kentucky, Lexington. These cables are subject to vertical frictional loading during filling, storing, and emptying operations. Since these cables are supported by the roof of a grain bin, designers require design guidelines for estimating the magnitudes and characteristics of the vertical loading. The loads imposed on temperature sensing cables have caused localized failures in certain components of grain bins as reported by Wickstrom (1980). The purpose of this study was to compare five different types of commercially available temperature sensing cables to determine the apparent coefficient of friction of wheat on the cables and the magnitude of vertical loading in a full-scale grain bin during both static and dynamic unloading conditions. The effects of emptying flow rate, starting grain height, detention time, and the radial position of the cables in the bin were determined. EXPERIMENTAL METHODS The experiments consisted of two parts: a laboratory study to determine the apparent dynamic coefficient of friction of grain on the cable surfaces; and a full-scale bin study to measure vertical frictional loading on the cables. Five types of temperature cables which represent several of the variations in commercially available cables were used in the experiments. The different dimensions and surfaces materials of the cables are given in Table 1 and the physical appearance is shown in figure 1. The cables used for the laboratory study were short sections identical to the cable specimens used in the bin study. The grain used was soft red winter wheat at 11.9% moisture content (wet basis) with an uncompacted bulk weight of 772.6 kg/m^. The influences of different variables on parameters measured were determined using analysis of variance technique in SAS (1982). The laboratory study was conducted to determine the apparent coefficient of friction of wheat on the temperature cables at different normal pressures. The magnitude of the