Atmospheric Test and Numerical Models Assessment of Annular Combustor on ZK2000 Gas Turbine

ZK2000 is a newly developed 2 MW all radial gas turbine with an annular combustor. In this paper, the authors present the atmospheric test results of the combustor on test rig. Evaluation of several RANS turbulence models and reaction models were used in order to determine which model was the most appropriate combination for comparison with the test results. FGM with SST were selected because of the better agreement with test results in terms of combustor temperature rise, primary zone temperature, liner metal temperature, and NO_x emission predictions.

Weatherability Studies on External Insulation Thermal System of Expanded Polystyrene Board,Polystyrene Granule and Polyurethane Foam

Atmospheric exposure tests including two experimental stages of high temperature-spraying water cycle and heating-refrigeration cycle were carried out on three currently used ETIS of expanded polystyrene（EPS） board,polystyrene granule mortar and polyurethane foam in order to study the weatherablility of external thermal insulation system（ETIS）.The change rules of adhesive strength were hereby studied at different time period of atmospheric exposure tests.The experimental results show that the adhesive strength of three kinds of ETIS changes a little during high temperature-spraying water cycle,but the adhesive strength of ETIS with EPS board decreases significantly after heating-refrigeration cycle.The lowering rate of adhesive strength with painting finishes is obviously faster than that of tile finishes for ETIS of EPS board during heating-refrigeration cycle.The weatherability of ETIS with EPS board is worse than the other two,and ETIS of polystyrene granule mortar and polyurethane foam are more suitable than ETIS of EPS board in cold area.

The Dynamical and Climate Tests of an Atmospheric General Circulation Model Using the Second-Order Adams-Bashforth Method

The Asselin-Robert time filter used in the leapfrog scheme can degrade the accuracy of calculations.The second-order Adams-Bashforth method with the same accuracy as the leapfrog scheme is not subject to time splitting instability.A new semi-implicit atmospheric general circulation spectral model is developed on the basis of NCAR（National Center for Atmospheric Research）CAM3.0（Community Atmosphere Model 3.0）.In this new model,the second-order Adams-Bashforth method is used as an alternative to the leapfrog scheme,and a Crank-Nicholson scheme is incorporated for the treatment of fast gravity modes.In this paper,the new model is tested by the Held-Suarez test and an idealized baroclinic wave test.Results of the Held-Suarez test show that the second-order Adams-Bashforth model has similar climate states to those of many other global models and it converges with resolutions.Based on the idealized baroclinic wave test,the capability of different time differencing methods for keeping the initial steady-state are compared. This convinces a better ability of the second-order Adams-Bashforth method in maintaining the stability of the initial state.Furthermore,after the baroclinic wave is triggered through overlaying the steady-state initial conditions with the zonal perturbation,the second-order Adams-Bashforth method has an excellent property of convergence,and can represent the process of the baroclinic wave development much better than the original scheme in CAM3.0.A long-term integration of the new model during the period of 1980–1999 is also carried out and compared with that of CAM3.0.It is found that due to the reduction of simulation errors of prognostic variables,the second-order Adams-Bashforth method also has a better simulation ability for the diagnostic variables,such as precipitation.