Advanced Materials Research Vols. 1070-1072

Abstract: Combustion characteristic of low calorific fuel gas in a pressurized porous burner was numerically investigated. The two-dimensional temperature profile, flame front, and CO concentration distribution were analyzed under the pressure at the certain operating parameters, and compared with those of the normal pressure. The results shows that the pressured temperature profile is more clear than that of the normal pressure, and maximum temperature distribution region is larger. Compared with the normal pressure, the pressured flame front location is at the downstream, and the flame propagation velocity along with inclination increases with the pressure increasing. The CO distribution is corresponding to the temperature profile. Its maximum locates at the position of the flame front, and gradually decreasing along the axial direction. It decreases with the pressure increasing, which indicates that the pressure contributes to improve the combustion efficiency.

Abstract: The condensation process of liquid-gas cross flow was mathematically modeled, and the expressions of heat and mass transfer coefficient were obtained. The characteristics of high temperature and humidity gas that flowed across an array of liquid columns were experimentally studied in various working conditions to get the heat and mass transfer coefficient. The results showed that: the heat and mass transfer coefficient of the staggered arrangement is 20~40% higher than that of the aligned arrangement; the gas turbulence near the gas-liquid interface caused by the flow of the liquid columns and that caused by the gas flow around liquid columns are the main factors that intensify the heat and mass transfer in low and high gas flow rate respectively.

Abstract: Introduces the technological process of the open heating system with a liquid-phase organic heat transfer fluids heater by analyzing the advantages and disadvantages of preventing heat transfer fluids from oxidation based on expansion pipe with cooling water casing. And it presents two methods to prevent heat transfer fluids from oxidation by arranging directly cooling coils or pulsating heat pipes in the expansion tank; it also provides the schematic diagram of those methods as well as comparatively analyzes their advantages and disadvantages.

Abstract: Through integrating the induced draft fan and desulphurization pressurization fan, the retrofited 300 MW coal-fired power unit can achieve lower power consumption rate. The operation economy has been improved, and it is also found that this retrofit can benefit the operation of both the boiler and gas desulfurization system. This work can provide valuable reference for the economic analysis of similar units.

Abstract: In order to investigate the influence of cooling efficiency of leading edge of film cooling blade with different turbulence intensity and blowing ratios,which use method of N-S equation,various blowing ratios of 1.0、1.5 and 2.0,various turbulence intensity of 5%、12%、20% and 30%,it simulated temperature field in leading edge of film cooling blade.The results show: cooling efficiency decreased when blowing ratios is increased.When turbulence intensity is 5%、12% and 20%,it obtains maximum cooling efficiency blowing ratios of 1.0.When turbulence intensity is 30%,it obtains maximum cooling efficiency blowing ratios of 1.5. In blowing ratios of 1.0,cooling efficiency decreased when turbulence increased.But in blowing ratios of 1.5 and 2.0,cooling efficiency increased when turbulence increased.

Abstract: This paper introduces the present research on engine thermal balance. It aims YC6MK natural gas engine as research project to carry out thermal balance test study. The test indicates that recycling engine residual heat and letting engine work under specified working condition are two ways of improving engine entire efficiency.

Abstract: For the efficiency measurement of coal-fired power plant has drawn attention widely, and then this article analyzed five power plants in China with a combination of PCA and DEA. Adjust of production parameters and strategies according to the method to improve the efficiency of power plants. This article proved that the method can make a breakthrough in evaluating performance of the power plants.

Abstract: This paper investigates experimentally the effects of spacer geometry on temperature difference ratio downstream of pressure side split of trailing edge film cooling. The internal pin fins arrayed staggered and pin fins in the last row face to the cooling hole one by one. The geometric parameters include relative length of trailing edge l/b, ratio of length to span of split a/c, ratio of length to width a/b, angle of split α. And the effects of blowing ratio and Reynolds number are also researched specially. The correlation of temperature difference ratio vs. Reynolds number, blowing ratio, and geometric parameters respectively was induced.

Abstract: Based on modified natural gas direct injection engine, we studied the impacts of ignition timing and jet timing on natural gas engine start process in this paper. The results shows that: when the first jet ignition occurs in the first compression stroke, the engine reaches idle speed 400rpm fastest; as the jet timing is delayed, emissions during engine start is gradually reduced, but when the jet late, HC surge occurs, the emissions deteriorates; with the ignition advance angle increasing, the engine speed growth accelerates, the peak moves forward; with the ignition advance angle increasing, HC emissions peak increases, the peak moves forward.

Abstract: Typical combustible particle coal has been analyzed by using turbulence-chemistry interaction models to realize which models are more accurate and reasonable on pulverized coal MILD combustion. Three turbulence-chemistry interaction models are examined: the Equilibrium Mixture Fraction/PDF (PDF), the Eddy Break Up (EBU), the Eddy Dissipation Concept (EDC). All of three models can give a suitable prediction of axial velocity on combustible particle coal MILD combustion because turbulence-chemistry interaction models have little influence on flow field and flow structure. The Eddy Dissipation Concept model (EDC), based on advanced turbulence-chemistry interaction with global and detailed kinetic mechanisms can produce satisfactory results on chemical and fluid dynamic behavior of combustible particle coal MILD combustion, especially on temperature and species concentrations.