Papers by Keyword: Radial Velocity

Abstract: The high altitude meteorological data is the basic parameters for weapon system trajectory calculation, firing ballistic correction, and ballistic standardization. Measurement range weapon testing is essential to evaluate the final results, so it is accurate or not will directly influence the test. This paper outlines the wind profiler radar in guided missile range experiment and the necessity of working mechanism, and gives the testing environment of radar range test application and erection of wind profiles and parameter setting, finally derived horizontal wind speed measurement precision, theoretical radial velocity measurement accuracy, as well as the theoretical horizontal wind. Making the range test of wind profiler radar measured data can fit the fast and the theoretical solution of data, in order to test application range stroke profile radar has a more comprehensive understanding, and application of more mature and rational.

Abstract: Radial velocity (RV) of a star caused by Doppler shift could be easily measured by cross-correlated it’s spectrum with a serial template. Generally, the RV error of a spectrum always is given by the widths of the cross-correlation function of the target spectrum and related template spectrum. RV error comes from many factors, causing from instruments, observation weather, etc.. In this paper, simulation with different types of stellar spectra, which has different temperature, is implemented. The results show that there is an internal error which is not generated by the calculation steps for a given resolution step, for example, 5km/s error exists in the cross-correlation based RV measurement method for resolution about R~2000. The simulation also proves that this error could not be avoided for any type of stars.

Abstract: Compressor is a crucial component of an engine. Flow through the compressor is intricate and sensitive to the reference frame, geometry of the blade, tip clearance, stator, staging etc. Compressor, though designed for a particular environment, is also expected to show its performance under off design conditions like accelerating flight, landing, take off, climbing etc. The flow in third dimension leads to many complications and ambiguity. Tip aerodynamics, passage flow, and vortex aerodynamics play crucial role in describing the flow through the upper half of the blade and in the tip region, whereas flow over blade surface, trailing edge and the hub will guide the aerodynamic behavior of the rotor blade. This exercise is done for off design environment to study the aforesaid flow characteristics and is carried on an axial flow fan. The performance variation of fan flow under varying flow conditions is analyzed.

Abstract: This paper presents computational fluid dynamics (CFD) studies to characterize air velocity distribution for various bed configurations in a swirling fluidized bed (SFB). Unlike conventional fluidized beds, a SFB provides radial mixing which is desirable is fluidization. Three velocities components were observed, the tangential velocity, radial velocity and axial velocity. These velocities were created as a result of using annular blade type distributor which mimics the turbine blades. In actual industrial applications, the axial velocity will create fluidization while the tangential velocity provides swirling effect. The presence of radial velocity can be explained as a consequence of centrifugal force generated by the swirling gas. Understanding these velocity distributions will enable optimization of the annular blade distributor design towards a high efficient fluidized bed system.

Abstract: On the base of numerical simulation and theoretical analysis, the flow field of a conventional single-tangential-inlet Hydrocyclone and a newly put forward axial-symmetry double-tangential-inlet hydrocyclone were contrasted. The study shows that the inlet structure of the Hydrocylone has a great influence on the radial velocity of the flow field in the hydrocyclone and that the radial velocity in the hydrocyclone with single-tangential-inlet is not symmetry about the axis of the hydrocyclone; and on the other hand the radial velocity in the hydrocyclone with axial-symmetry double-tangential-inlet is symmetry about the axis of the hydrocyclone. The magnitude of the radial velocity of the flow in the hydrocyclone with single-tangential-inlet is greater than that in the hydrocyclone with axial-symmetry double-tangential-inlet hydrocyclone, which means the hydrocyclone with axial-symmetry double-tangential-inlet has greater capability than the rival one with single-tangential inlet. The symmetry about the axis of the hydrocyclone of the radial velocity means the radial velocities in the place where the radio is the same are constant, which means the hydrocyclone has a great separation efficiency. The conclusion is that changing the conventional hydrocyclone into the one with axial-symmetry double-tangential-inlet structure can offer greater separation capability and efficiency.

Abstract: A fundamental study has been performed to analysis the fluid dynamic characteristics of the gas medium in a rotating disk cavity through the commercial software CFX11.0. This paper aims to discuss the impact of the speed of rotating disk, axial and radial size and parietal lubricant film velocity and other factors on the gas flow state in cavity. Several conclusions have been obtained: the speed of rotating disk has a great impact on velocity distribution of gas flow field; the dimensionless tangential velocity of the gas medium decreases along the radial direction, and with the speed increasing, it shows a certain regularity; Dimensionless radial velocity decreases along the radial direction, and the speed of rotating disk nearly has no influence on this; The shear stress distribution along the radial direction and the distribution of tangential velocity have similar regularity; the impact of disk cavity height on the distribution of the tangential velocity along radial direction in the gas flow field is much more obvious than the impact of disk cavity width.

Abstract: Radial velocity error of the spectra always be given by the widths of the cross-correlation function of the target spectrum and template spectrum. Radial velocity error affected by many inevitable factors, caused by instrument, observation weather, etc.. Another important error comes from calibration, which should be reduced as much as possible. This paper analysis the error based on different temperatures for different types of spectral. The effect of the calibration error to the radial velocity error is also presented.