Energy Output Characteristics Research Articles

One produced three: A capacitor-battery integration strategy in a dual-carbon device

Electrochemical energy storage (EES) devices having both high power density and high energy density are highly desirable. Although metal-ion hybrid capacitors (MIHCs) integrating a battery-type anode and a capacitor-type cathode are wished to realize this target, state-of-the-art MIHCs just showed the compromise performance between high-power supercapacitors (SCs) and high-energy metal-ion batteries. Herein, we propose a new concept of “device-level integration” to realize the integration of SC, MIHC and dual-ion battery (DIB) in one device. By coupling a mixed and pre-potassiated activated carbon (AC)/graphite anode and another mixed AC/graphite cathode in a K+-based organic electrolyte, as-built device can exhibit three distinctly different energy storage behaviors including SC, MIHC and DIB by simply tuning the applied voltage window. Consequently, this device is able to achieve the maximum power density at 0–2.8 V and the maximum energy density at 0–5.0 V, and exhibits a good combination of high power density and high energy density at 0–4.0 V. This work may open a new avenue for building advanced EES devices with adjustable power and energy output characteristics.

Optimization Design of Duct Geometry Based on Particle Swarm Optimization Algorithm

An optimization method for Darrieus turbine’s duct geometry is presented in this paper. In this method, the geometry parameters of the duct are used as optimal variables, and the energy output quality parameters of turbine are used as objective function. Then the particle swarm optimization (PSO) algorithm is introduced as search strategy to carry out the optimization of duct internal wall geometry. During the optimization procedure, the Kriging response model that meets accuracy requirement is used to replace the CFD simulation method, which offers significant time saving. According to the comparison of the energy output characteristics after the duct optimization, it can be found that the optimization of the duct internal wall geometry effectively improves the stability of the power coefficient. Meanwhile, the better energy-gathering effect also increases the power of the turbine. All these results indicate that the optimization method of duct geometry is feasible and effective

Study on Energy Output Characteristics of Explosives Containing B/Al in the Air Blast

It is a key problem to design and prepare metallized explosives of high energy and low sensitivity. In order to study the effect of the content of the boron/aluminum (B/Al) compound powder on the energy output property of metallized explosives in the air blast, three HMX-based explosives containing B/Al were designed and prepared. Air blast tests of cylindrical samples are performed, accompanied by numerical simulations by the finite element program LS-DYNA. The results show that the shock wave overpressures of explosives containing B/Al are higher than those of explosives containing Al under the same conditions. The deviations between the values calculated by the empirical equation and the measured values are smaller than 3.5 kPa, and the deviations between the values obtained in numerical simulations and the measured values are smaller than 4.9 kPa. Although the Al powder can enter the reaction with detonation products and air easier, the burning time of the boron powder is longer and the released energy is larger. Moreover, as the content of the B/Al compound powder increases, the burning time becomes longer, and the aftereffect work ability and the damage effect become stronger.

Investigation of energy output in mountain wind farm using multiple-units SCADA data

The energy output characteristics of mountain wind farms are more complex and unpredictable than that of flat wind farms because of complex mountainous terrain. Some questions about the energy output characteristics of mountain wind farms are still unclear. For example, the effect of local wind resource characteristics on the energy output of mountain wind farms. In another scenario, single-unit data from Supervisory Control and Data Acquisition (SCADA) system are used to investigate the performance of wind turbines in some cases. But, single-unit SCADA data may not be very comprehensive. To fill this gap, multiple-units SCADA data of 2 MW wind turbines are used to comparatively investigate the energy characteristics of wind turbines in a mountain wind farm. The main contribution of this paper is to obtain a new and comprehensive understanding of the actual characteristics of the energy output of mountain wind farms, rather than staying in the design stage or general theoretical analysis. Specifically, the following issues, including (1) influence of wind speed on energy output, (2) influence of wind direction on energy output, (3) relationship between rotor speed and energy output, (4) power coefficient, have been discussed in depth. To overcome the influence of inherent deviation in wind speed measurement and the inertia of the wind rotor, a newly improved algorithm for calculating power coefficient is proposed. Creatively, a fast and operable data dividing method is presented, and the power coefficients of different operating regions are given. Through the investigation, the influence of local wind resource characteristics on the energy output is obtained. It is found that in the same mountain wind farm, the energy output curves of different wind turbines are different. For instance, energy outputs for four wind turbines in December 2015 are 434 MW, 614 MW, 205 MW, 255 MW, respectively.

Study on Energy Output Characteristics of Explosives Containing B/Al in the Air Blast

Study on Energy Output Characteristics of Explosives Containing B/Al in the Air Blast

Energy characteristics of droplet transfer in wire-arc additive manufacturing based on the analysis of arc signals

The non-pulsed arc and pulsed arc were used in wire-arc additive manufacturing (WAAM) of aluminum alloys. Arc signals about arc current and voltage synchronized with the acoustic emission (AE) detected in manufacturing were used as information source to identify the droplet transfer mode. The calculations of probability density distribution, power spectrum distribution and energy gradient to synchronous time-domain signals were used to investigate the characteristics of metal droplet transfer and energy transfer. As a result, it was found that the characteristics of arc power signals and AE signals in WAAM process have a close relationship with the droplet transfer and arc ignition, and could reflect the variations of energy characteristics. The energy output characteristics of non-pulsed arc and pulsed arc during droplet transfer process are different. The matching of pulsed arc and pulsed droplet transfer mode obtains the best thermal and mechanical transfer characteristics, which is more suitable for the WAAM manufacturing process. No matter whether pulsed arc or non-pulsed arc is adopted, the energy output of arc should not be excessive, otherwise the energy output and the impact effect of arc and droplet transfer may be not conducive to the forming efficiency and quality of WAAM manufacturing.

Explosion Temperature and Dispersion Characteristics of Composite Charges Based on Different Non‐detonative Materials

The explosion fireball temperature and scattering process of explosive products of annular composite charges were investigated to guide the selection of non-detonative materials with controllable composite charge output. Overpressure sensors, an infrared thermal imager, and a high-velocity photography system were used to compare the explosive fireball temperature, scattering movement, and post-combustion characteristics of composite charges with different non-detonative materials. The fireball temperature distributions of the active non-detonative materials (rubber containing various proportions of aluminum powder) were not uniform, and the heat radiation power, heat flux, and overpressure were relatively high and first decreased and then increased with increasing aluminum powder content. The active non-detonative materials had two high-temperature regions in the lateral direction. Oxygen-free explosions, anaerobic combustion, and post-combustion processes occurred during the energy-release reaction of the composite charges. The temporal evolution of the throwing radius of the explosion products of the composite charges was investigated, and the rate of scattering of the non-detonative materials was analyzed. The rate of scattering was higher than that of an inert non-detonative material (polyurethane) and first increased and then decreased with increasing aluminum powder content. Based on the explosion-proof performance and heat radiation energy output characteristics, rubber containing 50 % aluminum was selected as the optimal non-detonative material.

New method of Q-switching with mode locking in solid-state lasers

A new method is proposed for performing a Q-switched laser operation with mode locking by using a spherical mirror (SM) and one traveling wave acousto-optic modulator (AOM), the SMAOM method. The temporal, spectral, and energy output characteristics of a diode-pumped Nd3+:YAG laser with SMAOM, along with the new results on obtaining powerful ultraviolet and mid-IR radiation based on the pumping of nonlinear crystals by such a laser, are presented.

Simulation of a multi-source hybrid heat pump system with seasonal thermal storage in cold regions

Based on taking full account of the building load and renewable energy output characteristics in cold regions, a multi-source hybrid heat pump system (MSHHPS) with seasonal thermal storage was proposed. The seasonal thermal storage comprehensively utilized solar energy, geothermal energy and air energy. The composition and operation modes of the system were introduced. The mathematical model of the main parts of the proposed system was established. The transition condition of the different operating modes of the system was determined. Taking a building in Harbin as the object for simulation analysis, the operation effect and the change of the soil temperature field of the system were obtained. The results showed that: The average coefficient of performance (COP) of the MSHHPS with seasonal thermal storage was 3.06 (in the Harbin region for 10years), the soil thermal balance rate was 100.33% and the energy-saving rate was 29.84% comparing to the ground source heat pump system (GSHPS). For the initial investment, MSHHPS only required additional double-source heat pump unit, which accounted at 9.59%. The static payback period of the double-source heat pump unit was 4years. The system can maintain efficient and economical operation in the typical cold regions.

Effect of Explosive Sources on the Elastic Wave Field of Explosions in Soils

A seismic wave is essentially an elastic wave, which propagates in the soil medium, with the strength of initial elastic wave being created by an explosion source that has a significant effect on seismic wave energy. In order to explore the explosive energy effect on output characteristics of the elastic wave field, four explosives with different work capacity (i.e., TNT, 8701, composition B and THL) were used to study the effects of elastic wave pressure and rise time of stress wave to the peak value of explosions in soils. All the experimental data was measured under the same geological conditions using a self-designed pressure measuring system. This study was based on the analysis of the initial pressure of elastic waves from the energy output characteristics of the explosives. The results show that this system is feasible for underground pressure tests, and the addition of aluminum powder increases the pressure of elastic waves and energy release of explosions in soils. The explosive used as a seismic energy source in petroleum and gas exploration should have properties of high explosion heat and low volume of explosion gas products.

A Numerical Study on Shock Wave Characteristics for the Underwater Explosion

Underwater explosion is very important for underwater weapons-design technology and research on the damage effect of target structure. In this paper, the flow-out boundary and variable step-size multi-material Euler algorithm were utilized to analyze numerically the whole process of shock wave generation and propagation, as well as bubble formation and impulse of underwater explosion. The computed results reveal the energy output characteristics of underwater explosion by TNT charge, which provide an important scientific basis for formulation design of charge and improvement of damage effects for underwater target.