Performance Of Tower Research Articles

Anti-Wind Experiments and Damage Prediction of Transmission Tower under Typhoon Conditions in Coastal Areas

Typhoons are a serious threat to transmission towers and lines in coastal areas. The anti-wind performance of a transmission tower needs to be reinforced and optimized to avoid tower collapse. Here, an improved real-time wind-field mathematical model and a tower-line coupled simulation model were established to reproduce the wind field distribution, mechanical vibration, and interaction between the wind field and tower. The damage prediction of the transmission tower was analyzed. Furthermore, an actual scaled tower-line model was built, which was used to measure the acceleration and displacement responses in the anti-wind experiments. The research results show that the improved model is feasible and correct based on the verification of Typhoon Mujigae. The tower’s vibration response is mainly characterized by low frequencies, whereas the lines indicate a high frequency response. The transmission line has a remarkable impact on tower vibrations in high turbulence. A flow direction angle of 50° and a long span are dangerous conditions for transmission systems in coastal regions. The acceleration and displacement responses of the main bars show opposite trends to that of the auxiliary cross-bars. The contribution of this article is the possibility of tower collapse prediction and prevention.

Numerical analysis of a counter-flow wet cooling tower and its plume

A one-dimensional model to study the heat and mass transfer inside and immediately above a wet counter-flow cooling tower is described. The wet cooling tower thermodynamic model assigns zone-specific Merkel numbers to each of the rain, fill, and spray zones, and it includes an atmospheric plume model. Using the present formulation, zone-by-zone rates of heat rejection and water evaporation can be estimated, as can the visible plume height. The model is validated against the well-established Poppe and Merkel methods as well as select field data. Cooling tower performance and plume visibility are evaluated under a variety of climatic conditions (hot-dry, hot-humid, cool-dry and cool-humid), cooling tower designs (e.g. fill zone height, H f z ), and operating conditions (e.g. water-to-air mass flow rate ratio, L / G ). The parametric study in question highlights the ability of the proposed model to predict the impact of ambient conditions, cooling tower design parameters, and operating conditions on overall performance and patterns of atmospheric dispersion. The proposed model is ideal for numerical optimization of cooling towers that need to meet stringent thermal performance and plume visibility requirements. • A coupled one-dimensional cooling tower and plume model is developed. • Heat transfer in each zone of the tower analyzed at varying ambient conditions. • Plume visibility at different air flow rates studied at varying ambient conditions.

Transmission Tower Earthing Design for Lightning Condition in Malaysia’s Power Grid

The transmission tower earthing design is installed under the ground to protect nearby personnel and equipment, as well as to improve the line lightning performance. The previous tower earthing design in Malaysia’s grid system was tailored for normal power frequency fault, which are low-frequency in nature. This tower earthing design was not suitable during lightning fault, which is of higher frequency. The previous earthing design practice involves installing radial counterpoises up to 120 meters horizontally from each tower legs to get the tower footing resistance (TFR) reading of 10 Ω or less. This practice is proven to be ineffective in lowering the resistance at higher frequency i.e. lightning strike. This paper discusses a new compact earthing design that has low impedance value at low and high-frequency. The performance of this new earthing design were simulated at various soil resistivity values over a frequency range, and were compared to the performance of previous tower earthing design. The new earthing design were also installed on a number 500kV, 275kV and 132kV towers and their TFR were measured using both low and high-frequency TFR meters. The proposed concentrated earthing design was shown to have low impedance value at both low and high-frequency domain.

Numerical and full-scale test case studies on post-elastic performance of transmission towers

Post-elastic capacity of transmission tower is critical for the realistic assessment of tower vulnerability under the extreme loading conditions. This paper first presented a series of numerical simulations of a lattice transmission tower section under torsional (longitudinal) or bending (transverse) loading in both static and dynamic scenarios. From the results of the numerical simulations, four prototypes of lattice transmission towers were constructed and tested for the investigation of the post-elastic performances of the towers under different loading conditions. The tests results showed that there existed significant post-elastic strength reserve of the tower under investigation. For the towers tested in this research, the post-elastic strength reserve was 1.22 for flexure-torsion (i.e. tower under longitudinal loading) governed by diagonals, and 1.37 for bending (i.e. tower in transverse loading) governed by inelastic buckling of the main legs. Diagonal members affected the failure modes of transmission towers and their connection design may be a weak link in the development of their post-elastic capacity.

Failure Analysis of Transmission Tower in Full-Scale Tests

With the rapid development of Ultra-High Voltage (UHV) transmission lines, it is necessary to study the performance of UHV transmission towers. First, we performed full-scale tests on a transmission tower under seven loading patterns. Then, the test results were compared with the calculation results of the Chinese tower design software Transmission Tower Analysis Program (TTA), and the failure location of the tower and the stress characteristics of the key parts were studied. Finally, we discuss the influence of bolt slippage and a new joint on the tower performance, and propose some design proposals for the current Chinese code, based on the test results. The results show that a bolt slip will significantly increase the displacement of the transmission tower, but the residual displacement can correct it. The new joint design has good mechanical performance. The bracing member at the bottom of the tower leg is located at the connection of the tower leg and the foundation, and there is a significant sudden change in stiffness, which we recommend designing according to 4% of the axial force of the main members.

Numerical investigation of a novel cooling vortex tower using Relap5 computer code

The main objective of this work consists of modeling, simulation and analysis of the kinematic, dynamic and thermal characteristics of airflow through a novel vortex tower model carried out at the Nuclear Research Center of Birine (Algeria). This work is a contribution to a project aiming to study and design a vortex tower prototype based on an airflow heated by the secondary circuit of a nuclear reactor. The purpose of this process is to use the lost energy, traditionally transferred to the environment to cool a facility, to generate an additional amount of electrical energy. The main issue to be resolved in this study is to identify the appropriate location in the flow path where the flow characteristics are the most suitable to recover the maximum electrical energy using a turbo generator.The work presented in this paper is to investigate the airflow characteristics and predict the behavior of the vortex tower model using Relap5 system code in spite of the chaotic nature of the flow in such geometry. In addition, a parametric study is carried out in order to identify the effect of some parameters on the tower performance such as the air inlet velocity ranging from 0.01 to 0.3 m/s and the number of inlet openings varied from 1 to 8.Vortex model geometry is created and nodalized according to Relap5 system code modeling guidance and requirements. The developed model was qualified against experimental and numerical results available in the literature in terms of velocity quantities, as well as with an analytical calculation using the mass balance, a good agreement was obtained. The analysis of the simulation results showed that the selected tower configuration presents good characteristics with a maximum air velocity of 5.5411 m/s at a height of 0.560 m from the base (inlet section). The simulation highlighted clearly the contribution of the inlet parameters and the number of inlet openings to the enhancement of the vortex tower performances. The investigations revealed that an increase in air inlet velocity until 0.3 m/s leads to an increase of air velocity at the narrowing point of the tower attaining a maximum of 16.217 m/s. Furthermore, the results also showed that the maximum airflow velocity increases by 87 % when the number of air inlet openings is varied from 1 to 8.

Research on performance of passive heat supply tower based on the back propagation neural network

In this study, the performance parameters of passive heat supply tower (PHST) were analyzed. The optimal daily water-air ratio of PHST was obtained using non dominated sorting genetic algorithm (NSGA-II), BP neural network algorithm and decision score (DMS). The energy saving potential and energy efficiency ratio range of 48.8–50.8 were obtained for PHST operation with the air parameters corresponding to the optimal water-to-air ratio. The study shows that PHST has superior energy-saving characteristics when used to supplement heat for underground soil. The BP neural network model can accurately calculate and predict the variation of PHST performance parameters. Higher energy efficiency of PHST system can be obtained by effectively controlling the water-air ratio. This study provides a new scheme for the operation of the supplementary heat system and a new idea for the efficient operation of the heat exchange equipment.

Comparative studies on performance of solar towers with variable scale ratios.

Improvements in the geometry of solar towers are explained in this study. Both computational and experimental studies are carried out. Three different solar towers of 1:60, 1:70, and 1:122 scale ratios are taken for the study. All the studies are carried out in an open atmosphere, where a hot wire anemometer is used to measure the peak velocity at the collector-tower junction. The collector geometry is kept flat, inclined, and semi-divergent. The tower geometry is modified from the straight tower into semi-divergent and fully divergent towers. The fully divergent tower with a semi-convergent collector achieves the highest power output among the other two models. The area convergence is the prime factor for an increase in peak velocity. The divergent tower with a semi-convergent collector achieves 54% more power output than a cylindrical tower with a flat collector.

Heat balance analysis of RSG-GAS coolant system due to cooling tower refurbishment

The RSG-GAS reactor is designed to operate at a power level of 30MW, as stated in the Safety Analysis Report, and currently RSG GAS has been operating for 34 years. Aging of components has been anticipated to ensure the reactor operates safely. Some parts of the structure, system and components (SSC) will experience degradation/aging and must be replaced. Cooling tower is one of them, where the sub components are maintained and tested regularly. Cooling tower aging indication are known from the decreased performance of the reactor cooling system. For this reason, it is necessary to evaluate, both in terms of measurement and calculation analysis, before and after the refurbishment. The efficiency of the cooling tower has been calculated based on the measurement results of the cooling temperature, at the RSG-GAS operation at a power level of 30 MW. From the measurement results, it can be seen that there is a difference in air velocity inlet and outlet of module 1 and module 2. As well as the working temperature of the blower is uneven, the blower temperature ranges from 60.5°C-91.9°C. So that the operation of the RSG GAS could not last long. The efficiency of the cooling tower during the day ranges from 54.72% to 73.23%. The effect of decreasing cooling tower capability can be seen from the calculation results on the performance of each module individually. while its effect on the overall performance is known from the increase in the temperature of the coolant entering the reactor from the HE. The results of the cooling temperature measurement, after refurbishment, show that the cooling tower performance has been able to dissipate heat according to the initial design.

Hierarchical Transmission Tower Detection from High-Resolution SAR Image

The small scale of transmission towers and the environmental diversity around their situations make their detection in Synthetic Aperture Radar (SAR) images a challenging task. This paper presents a new hierarchical detection algorithm for transmission towers. First, Signal-to-Clutter Ratios (SCRs) of pixels are calculated. Afterwards, a SCR threshold is set. Since transmission towers possess strong scattering characteristics, pixels with SCRs above the threshold are considered as potential transmission tower pixels. Second, spatial densities of potential transmission tower pixels are calculated. According to the aggregation characteristics of transmission tower pixels, some potential transmission tower pixels with small spatial densities are removed. The remained potential transmission tower pixels are considered as candidate transmission tower pixels. The candidate transmission tower pixels are grouped by the nearest neighbour scheme such that in each group the distance between pixels is under a given threshold. Thus, each of the groups is viewed as a quasi-transmission tower. Convex-hulls of quasi-transmission towers are built, and then Minimum Bounding Rectangle (MBR) for each convex-hull is generated. According to the rectangle aspect ratios of MBRs, the real transmission towers are extracted. C-band HH-polarization GaoFen-3 (GF-3) amplitude images are used for experiments and four of the most popular transmission tower detection algorithms are selected as comparing algorithms to validate the proposed algorithms. The detection performance of transmission towers is evaluated with detection rate and quality factor. Experimental results verify that the proposed algorithm can efficiently and accurately detect transmission towers while maintaining the transmission tower geometry to a certain extent, which indicates that the proposed algorithm is efficient and promising.

Seismic performance of a wind turbine tower under near-field vertical earthquake excitation

For researching the influence of vertical component of near-field records on the seismic response of wind turbine towers, firstly, shaking table test of a 1/20 scaled 2.0 MW wind turbine is carried out. Second, the finite element (FE) model of the scaled tested model is established by ABAQUS. Finally, the dynamic stability is analysed based on the validated FE model. Moreover, the sensitivity of seismic response to different V/H ratios (peak vertical acceleration to horizontal acceleration) of near-field records is analysed through experimental and numerical studies. The results show that the near-field earthquakes have a greater effect on the acceleration and displacement response. The vertical acceleration, vertical displacement and the axial force of this tower are sensitive to the vertical ground motions and the V/H ratios. The larger contributions of vertical component of near-field ground motions lead to smaller safety factors, which is particularly more unfavourable for the dynamic stability of this tower. The middle and lower section of this tower is the dangerous position for local buckling. The influence of the near-field vertical ground motions and a reasonable value of V/H ratios should be better understood and studied, so as to provide guidance for structural seismic design.

Influence of New Vertical Corrugated Packing on Thermal Performance of Cooling Tower

Influence of New Vertical Corrugated Packing on Thermal Performance of Cooling Tower

Simulation study on photon generation and collection of tower applied to NICA-MPD electromagnetic calorimeter

Shashlik tower, which is composed of absorbers and scintillators alternately, surrounded by reflector and coupled with Silicon Photomultiplier (SiPM) by Wavelength-Shifting (WLS) fibers, is a significant component to measure the energy and position of photons and electrons in Electromagnetic Calorimeter (ECal), a key detector of the Multi Purpose Detector (MPD) at the Nuclotron-based Ion Collider facility (NICA) in Russia. In this paper, the effect of materials adopted for absorber, reflector and WLS fiber, the length and curvature of fibers and the electrons incident position on photons transmission performance of tower is simulated based on GEANT4 software. The impact of Gaussian deviation's electron beam energy and spread of 10% in the energy range on the energy resolution of tower is also studied. Results show that the low polishing degree absorber, the high polishing degree TiO_2 reflector and the type of Y-11 WLS fibers bent with a curvature radius of greater than 11 cm can significantly improve the light output. In addition, electrons injected along the centre of tower can make photons position distribution in SiPM more uniform. The generation time of photons in scintillators and time of arrival at the SiPM both obey the Landau distribution. Finally, the energy resolution of tower can be better than 3.8%/√(E) (GeV) for a Gaussian deviation's electron beam with an average energy of 3 GeV and spread of 10% in the energy range.

Effect of the Collector's Cover Material on Solar Updraft Tower Performance: An Experimental Assessment

Effect of the Collector's Cover Material on Solar Updraft Tower Performance: An Experimental Assessment

Enhancing cooling tower performance with condition monitoring and machine learning based drift detection

Process cooling is crucial to many manufacturing processes. To monitor the performance of a cooling tower, it was equipped with extensive sensors for internal and environmental data acquisition. The aim is to improve reactive and predictive maintenance by estimating the actual condition as well as predicting defective behavior of the cooling tower. We designed a method, which derives the degree of defect from data of the non-defective cooling tower. A concept drift detection approach was implemented, which monitors the model estimation error of a multilayer perceptron model. Increasing model estimation error indicates changing system behavior and increasing risk of failure.

Optimizing the collector inlet height of a divergent solar tower using response surface methodology

In this work the response surface methodology (RSM) was adopted to investigate the effect of inlet height of collector on the performance of divergent tower. The traditional computational methods are replaced by RSM to validate the experimental values. The methodology proposed in this work was carried on a 1:60 ratio divergent solar tower with inclined collector experiment model. The collector inlet height was kept constant and the outlet height was varied for three different values. The air properties namely the velocity of the buoyancy air and the temperature at the chimney base were measured using hot wire anemometer and by temperature sensors respectively. The measurement of air velocity and temperature were taken at the three locations. The experimental findings were analyzed to find the optimized geometry for the collector inlet opening height. According to a comparison between the results obtained by the proposed method and the actual model-based global algorithm, the high accuracy and low computation time of the proposed strategy was proved. Also, Optimized value of the inlet opening was determined by RSM.

CFD investigation of a natural ventilation wind tower system with solid tube banks heat recovery for mild-cold climate

Passive strategies are increasingly being employed in buildings to minimize their total energy consumption and emissions. Wind tower, a natural ventilation device, can capture the wind flow from higher locations and supply the air into the buildings' indoor space without consuming electric power. However, its use in mild-cold climate is limited due to excessive heat loss and thermal discomfort, in particular, during winter. Limited research has been conducted to explore the pre-heating of the supply air in the wind tower to address the issue and potentially increase its adoption in mild-cold climates. Therefore, a novel wind tower ventilation system integrated with solid tube banks heat recovery (HR) is proposed in this research. By combining with a passive heat recovery device, a wind tower can be operated under winter conditions to improve indoor ventilation while reducing the building heating energy consumption. A three-dimensional computational fluid dynamics (CFD) model was developed to investigate the effects of the longitudinal pitch (SL) and the transverse pitch (ST) of the HR device on the ventilation and thermal performance. The overall performance of the wind tower was evaluated under different outdoor wind speeds. The results show that the heat recovery can be improved by reducing SL and ST, raising the supply fresh air temperature by up to 6.4 °C. Furthermore, the proposed wind tower can provide sufficient ventilation for a typical classroom occupied by 15 people when the external wind speed exceeds 3 m/s.

Integration of the Intelligent Optimisation Algorithms with the Artificial Neural Networks to predict the performance of a counter flow wet cooling tower with rotational packing

The present study investigated a counter-flow cooling tower performance by integrating the Artificial Neural Networks and Intelligent Optimisation Algorithms (ANN-IOAs). For this purpose, two scenarios were evaluated. In the first scenario, inlet air wet-bulb temperature (T aw), inlet air dry bulb temperature (T ad), water to the air mass flow rate ratio (mw /ma ), and rotor speed (υ) were the input parameters for the ANNs, while the output temperature (T wo) was the ANNs output. In the second scenario, the same input parameters applied for the first scenario were used as input variables and the tower efficiency (ε) was considered as an output parameter. The well-known IOAs methods, namely, Genetic Algorithm (GA), Particle Swarm Optimisation (PSO) and Bees Algorithm (BA), were used to optimise the ANNs for both scenarios. The obtained results showed remarkable accuracy for the proposed ANNs. The designed ANN model based on the BA method predicted the most efficient results. A sensitivity analysis was performed to study the most effective input parameters on the output temperature and the tower efficiency. Finally, for demonstrating the accuracy of the proposed ANN models for each case, a fair comparison is made between the proposed ANN models and regression models.

Effect of Tower Height and Collector Radius on Performance of Solar Updraft Tower Power Plant

A renewable energy resource like solar energy that is abundant in nature and eco-friendly, is a better alternative for electricity generation. Solar energy is already being used to produce electricity with the help of photo-voltaic panels and among many other technologies solar updraft power plant is a noble promising technology which can be used to supply power to countries with large wastelands or unused desert lands. In this study, the temperature and velocity values that affect the performance of solar tower are analyzed for different chimney height and collector surface areas. The simulation of the Solar Updraft Tower was performed with Energy2D software based on computational physics. It was analyzed that the increase in tower height and collector surface area significantly increased the temperature and velocity values of the air flowing from the collector mouth inlet to the center. As a result, when different solar updraft tower models were compared, the most important factor affecting the performance of the solar chimney was the chimney length and the collector surface area.

Performance analysis of roof collector used in the solar updraft tower

The solar collector is the heart of the solar updraft tower as the solar updraft tower's performance depends on the generation of solar energy under the collector roof. Hence, the current research work's objective is to analyze the performance of various roof collector materials used in the solar updraft tower. An experimental set-up of a solar updraft tower was developed and installed in Nagpur, India, in the year 2018. Experimentation was carried out using different roof collector materials like glass, acrylic sheet, polycarbonate sheet and crystalline sheet at a chimney height of 4.8 m and 3.6 m. The results showed that by increasing the 33.33% height of the chimney from 3.6 m to 4.8 m, output power rises 37.92%, 36.13%, 16.78% and 32.18% for glass, acrylic, crystalline and polycarbonate sheet as the collector roof material respectively. The system's output power increases in the range of 5% to 15% with the glass as the roof collector material compared to the acrylic sheet, crystalline sheet, and polycarbonate sheet. The experimental values are compared with analytical values of the power developed, and these were found to be in good agreement, thus validating the experimentation.