Advanced Materials Research Vols. 860-863

Abstract: In order to ensure proper temperatures for electronic equipment and to meet the increasing heat dissipation capacity needs of airborne electronic equipment, a suitable heat-pipe for use in aircraft equipment needs to be found. Considering both the acceleration and the changes in tilt angle of the aircraft, performance analysis of five main types of heat-pipes showed that dual compensation chamber loop heat pipe and micro-channel plate heat pipe were the most suitable for use in airborne electrical equipment.

Abstract: The influence of bluff-body structural parameters and incoming velocity on the cold flow field of advanced vortex combustor (AVC) has been studied, and the results show that the vortex in cavity can be the most stable and the total pressure loss can be the least when structural parameter is B2/B1=0.7, L/B1=0.8. The incoming velocity should not be too high or too low, it should be combined with specific structural parameters of the combustor, the combustion flame speed, fuel type, and the stoichiometric ratio and other factors. If AVC design is reasonable, the cavity can not only stabilize the flame, but also not be sensitive to the speed changes.

Abstract: Accurate temperature measurement needs in both research and industry have become more demanding and traditional temperature measurement technologies are struggling to keep up. Optical fiber thermometers have many unique advantages and are an option with much potential in the area of high temperature measurement. Research shows that fiber optic temperature sensors are capable of making accurate and precise measurements in a wide range of harsh conditions where other measurement technologies cannot and are a cost effective option in situations where traditional measurement technologies are currently used. Several typical high temperature fiber optic sensors are discussed in detail, focusing on the principle of operation, advantageous characteristics, and recent research developments, with the aim of aiding in further work with fiber optic thermometers.

Abstract: The combustion stability of pulverized coal is very essential for utility boilers. That is the key issue to keep the operation of the whole power-generation unit in a safe state. The amount of volatile matter is used to anticipate the combustion state of pulverized coal. As a widely accepted concept, higher volatile matter content would result in more stable combustion state. But in some cases, the coal with high volatile matter content led to poor combustion states, even resulted in the flameout of the burner. More method is needed to judge the coal and to predict the combustion stability. With research on the approximate analysis of the coal composition, the heat value of volatile matter was calculated. Such heat value varies obviously for different kinds of coal. The ratio of the heat value of volatile matter to the heat value of fixed carbon is supposed to describe the combustion stability of pulverized coal. The application of the method judges the coal better than using the amount of volatile matter alone.

Abstract: Oxide scales have negative effects on the security and economy of supercritical and ultra-supercritical units.The finite volume method was exploited to simulate oxide scales growth temperature on the inside of superheater tube,then the appropriate time and spatial intervals were selected to calculate oxide scales thickness along the circumferential direction with the correspond growth temperature.At last,the stress response of the oxides was simulated with finite element method.The simulated temperature is closed to the analytical temperature, confirming that the simulation results are credible.The results show that the growth temperature rises fast at the beginning and drops in the circumferential direction,which changes rapidly at the 90°. Oxide scales thickness is thinner and thinner in the circumferential direction and changes fast at approximately 90°.Though the magnitude of circumferential stress and axial stress is different, but the trend same.The simulation results can provides a theoretical basis for the failure research of the oxide scales.

Abstract: Entrainedflow Gasifier with Large Capacity and Slagging Tap is Usually Use for IGCC and Largescale Chemical Industrial Factory. while, there are 57% of Reserved Coal is Highfusion Temperature Coal, which Cannot Satisfy the Requirement of Thegasification for Slagging Tap. . Therefore, Two Typical Kinds of Chinese Coals Wereselected and Gasified in a Lab-Scale down-Flow Gasifier with Feeding Rate Ataround 1kg/h. the Results Show that along with the Increasing Temperature, Thecarbon Conversion and Cold Gas Efficiency will be Increased Quickly Whentemperature is below 1400°C, and then Increased Slowly when above 1400°C. the Optimum O/C Molarratio is around 1:1, the Cold Gas Efficiency and Carbon Conversion under Thisexperimental Condition (1300-1400°C) are Separately 31% and 80%. at the Optimumgasification Condition, Increasing the Residence Time will also Increase Thecoal Gas Concentration, Carbon Conversion and Cold Gas Efficiency. under Thisexperimental Condition, the Best Residence Time is at Least 1.5~2.0s.

Abstract: Environmental cross-wind has a influence on cooling capacity of wet cooling tower to a great extent in power plant.The variation of circulating-water temperature difference (Δt) and cooling coefficient of efficiency(η) with cross-wind velocity, circulating water inlet temperature and flow rate, are shown under cross-wind conditions, compared with cases without wind. By using experimental platform of cooling water system based on 300MW thermal power unit,it is found that with cross-wind velocity increasing,cooling temperature difference and cooling efficiency decrease first then increase at the knee point when the velocity value is 0.8m/s. In addition, the correlation betweenΔt ,η and parameters,such as circulating-water inlet temperature and flow rate, is derived for cases with windless conditions.

Abstract: According to the structure and working principle of rotary air preheater,the heat transfer calculation model is set up with reasonable simplification. Combining with the design parameters of the rotary air preheater of a 400 t/h pulverized coal boiler unit ,the results of practical calculation show that the said thermodynamic calculation method not only has higher precision of calculation,but also can get the temperature distributions of the gas, air and heat surface in each cross-section of the rotary air preheater. The result of numerical simulation calculation tallies well with the original designed data. It can be used for the heat calculation both two-sectorial and three-sectorial air heater; it can be used for performance analysis of the regenerative air heater.

Abstract: Electricity and high-temperature heating steam are the products of marine diesel enginecogeneration system, and the heat-electricity cost allocation ratio impact cogeneration systemoptimization directly. This paper described several existing cost allocation methods, and applied thereduced exergy method to specific marine diesel engine cogeneration system, then, established thecost allocation model to derive the detailed process and results of calculating heat-electricity costallocation ratio, and draw an conclusion that the reduced exergy method is the most reasonablemethod of cost allocation.

Abstract: In order to fit in with the demands of the development of electricity market in China, a multi-objective optimization mathematical model is presented to dispatch load within the units, taking economy, environmental protection and quick responsiveness to dispatching commands into consideration at the same time. And take the minimal whole plants power-supply coal cost rate, the minimal pollutant emissions and the minimal load adjusting time as these three objective functions respectively. The four constraint conditions are unit power balance constraint, load bound constraint, ramping constraint and pollution discharge standards constraint. An improved particle swarm optimization algorithm is used to get the Pareto solution set. The optimal solution was obtained by using the method of multi-attribute decision making, through sequencing the solution set by comprehensive evaluation. A case study based on a power plant with 4×600MW units was carried out. The result shows that the method can solve the multi-objective optimal load distribution problem accurately and quickly, and get the good effect in energy conservation and emissions reduction.