Optimization of the Gas Generator in Composite Power System with Tip-Jet Rotor

The key and bottleneck of research on the tip-jet rotor compound helicopter lies in the power system. Computational Fluid Dynamics (CFD) was used to numerically simulate the gas generator and rotor inner passage of the tip-jet rotor composite power system, studying the effects of intake mode, inner cavity structure, propellant components, and injection amount on the characteristics of the composite power system. The results show that when a single high-temperature exhaust gas enters, the gas generator outlet fluid is uneven and asymmetric;when two-way high-temperature exhaust gas enters, the outlet temperature of the gas generator with a tilted inlet is more uniform than that with a vertical inlet;adding an inner cavity improves the temperature and velocity distribution of the gas generator's internal flow field;increasing the energy of the propellant is beneficial for improving the available moment.

Numerical investigation on cooling performance of filter in a pyrotechnic gas generator

As a key part of the pyrotechnic gas generator,the filter not only removes the particulate matter but also cools the hot gas to a safe level.This paper aims to improve the understanding of the basic heat and flow phenomenon in the gas generator.The pyrotechnic gas generator is modelling by a simplified filter structure with fiber arrays.A finite-volume model of the heat and fluid flow is proposed to simulate the detailed multi-dimensional flow and energy conversion behaviors.Several verification results are in good agreement with data in different references.Simulation results demonstrate that the filter can not only absorb heat from the gas but also cause the high intensity enhancement of the heat transfer.The performance difference between inline and staggered arrays is also discussed.The findings of the study put a further prediction tool for the understanding and design of the filter system with fibers.

Forecasting of China's natural gas production and its policy implications

With the vigorous promotion of energy conservation and implementation of clean energy strategies,China＇s natural gas industry has entered a rapid development phase,and natural gas is playing an increasingly important role in China＇s energy structure.This paper uses a Generalized Weng model to forecast Chinese regional natural gas production,where accuracy and reasonableness compared with other predictions are enhanced by taking remaining estimated recoverable resources as a criterion.The forecast shows that China＇s natural gas production will maintain a rapid growth with peak gas of 323 billion cubic meters a year coming in 2036;in 2020,natural gas production will surpass that of oil to become a more important source of energy.Natural gas will play an important role in optimizing China＇s energy consumption structure and will be a strategic replacement of oil.This will require that exploration and development of conventional natural gas is highly valued and its industrial development to be reasonably planned.As well,full use should be made of domestic and international markets.Initiative should also be taken in the exploration and development of unconventional and deepwater gas,which shall form a complement to the development of China＇s conventional natural gas industry.

Observational constraints on the new generalized Chaplygin gas model

We use the latest data to investigate observational constraints on the new generalized Chaplygin gas （NGCG） model. Using the Markov Chain Monte Carlo method, we constrain the NGCG model with type Ia supernovae from the Union2 set （557 data）, the usual baryonic acoustic oscillation （BAO） observation from the spectroscopic Sloan Digital Sky Survey data release 7 galaxy sample, the cosmic mi- crowave background observation from the 7-year Wilkinson Microwave Anisotropy Probe results, newly revised data on H（z）, as well as a value of θBAO （Z = 0.55） = （3.90° ±0.38°） for the angular BAO scale. The constraint results for the NGCG model are ωX=-1.0510＋0.1563-0.1685（1σ）＋0.2226-0.2398（2σ）,η=1.0117＋0.0469-0.0502（1σ）＋0.0693-0.0716（2σ）and ΩX=0.7297＋0.0229-0.0276（1σ）＋0.0329-0.0402（2σ）, which give a rather stringent constraint. From the results, we can see that a phantom model is slightly favored and the proba- bility that energy transfers from dark matter to dark energy is a little larger than the inverse.

Constraining the Generalized and Superfluid Chaplygin Gas Models with the Sandage-Loeb Test

The Sandage Loeb （SL） test is a direct measurement of the cosmic expansion by probing the redshift drifts of quasi-stellar objects in the ＇redshift desert＇ of 2 〈 z 〈 5. In this work, we investigate its constraints on the unified dark energy and dark matter models including the generalized Chaplygin gas and the superfluid Chaplygin gas. In addition, type Ia supernovae （SNIa） data and the distance ratios derived from the cosmic microwave background radiation and baryon acoustic oscillation observations （CMB/BAO） are also used. We find that the mock SL data gives the tightest constraints on the model parameters and it can help to reduce the parameter regions allowed by the present SNIa＋CMB/BAO by about 75% when all datasets considered are combined. Thus the SL test is a worthy and long awaited measurement to probe effectively the cosmic expanding history and the properties of dark energy.

Wave Interactions of the Aw-Rascle Model for Generalized Chaplygin Gas

In this paper, we investigate the elementary wave interactions of the Aw-Rascle model for the generalized Chaplygin gas. We construct the unique solution by the characteristic analysis method and obtain the stability of the corresponding Riemann solutions under such small perturbations on the initial values. We find that the elementary wave interactions have a much more simple structure for Temple class than general systems of conservation laws. It is important to study the elementary waves interactions of the traffic flow system for the generalized Chaplygin gas not only because of their significance in practical applications in the traffic flow system, but also because of their basic role for the general mathematical theory.

Universe Filled with Generalized Cosmic Chaplygin Gas and Barotropic Fluid

In this paper we have considered a model of the universe filled with Generalized Cosmic Chaplygin Gas and another fluid with barotropic equation of state. We observe its role in accelerating phase of the universe by considering the mixture of these two fluid models valid from the radiation era to for and the radiation era to quintessence model for . The statefinder parameters describe the evolution of the universe in different phases for these two fluid models.

Constraints on the unified model of dark matter and dark energy

Using recently observed data： the Constitution dataset of type supernovae Ia （SNIa）, the observational Hubble data （OHD）, the measurement results of baryon acoustic oscillation （BAO） from the Sloan Digital Sky Survey （SDSS） and the Two Degree Field Galaxy Redshift Survey （2dFGRS）, and the current cosmic microwave background （CMB） data from the five-year Wilkinson Microwave Anisotropy Probe （WMAP）, we apply the Markov Chain Monte Carlo method to investigate the observational constraints on the generalized Chaplygin gas （GCG） model as the unification of dark matter and dark energy. For this unified model, the constraints on GCG mixture are discussed by considering the different expressions of current matter density or considering constraints as being independent of the matter quantity Ωm.