Measurement Enhancement on Two-Dimensional Temperature Distribution of Methane-Air Premixed Flame Using SMART Algorithm in CT-TDLAS

In this study, the temperature distribution of the Methane-Air premixed flame was measured. In order to enhance the measurement accuracy of the CT-TDLAS (Computed tomography-tunable diode laser absorption spectroscopy), the SMART (simultaneous multiplicative algebraic reconstruction technique) algorithm has been adopted. Further, the SLOS (summation of line of sight) and the CSLOS (corrective summation of line of sight) methods have been adopted to increase measurement accuracies. It has been verified that the relative error for the temperatures measured by the thermocouples and calculated by the CT-TDLAS was about 10%

Impact of Magnetic Field on Convective Flow of a Micropolar Fluid with two Parallel Heat Source

A numerical study is performed to analysis the buoyancy convection induced by the parallel heated baffles in an inclined square cavity. The two side walls of the cavity are maintained at a constant temperature. A uniformly thin heated plate is placed at the centre of the cavity. The horizontal top and bottom walls are adiabatic. Numerical solutions of governing equations are obtained using the finite volume method coupled with the upwind and central difference technique. Numerical results of the two-dimensional flow field governed by the Navier-Stokes equations are obtained over a wide range of physical parameters, namely the Rayleigh number, the Hartmann number, the inclined angle of the magnetic parameter and the vortex viscosity parameter. It is observed from the results, the heat transfer rate is reduced when increasing Hartmann number, inclination angle and vortex viscosity parameter. The higher heat transfer rate is obtained based on the Newtonian fluid compared to the micropolar fluid

Measurement of Three-Dimensional Combustion Distribution using CT-TDLAS

에너지 자원을 효율적으로 사용하기 위해서는 연소 가스에 대한 정확한 측정이 필요하다. TDLAS 기술로 대상 가스의 온도와 농도를 동시 측정할 수 있다. 현재 가스의 정밀 제어가 필요한 산업공정에 2차원 또는 3차원의 정보를 측정한 실험적 보고는 미비하다. 본 연구에서는 산업공정의 연소를 제어하 고 모니터링하고자 CT-TDLAS 시스템을 이용한다. 메탄-공기 예혼합화염의 3차원 온도 분포는 CT-TDLAS 시스템에 의해 측정되었으며, 3차원 온도 분포는 2차원 셀의 5개 층으로 측정하였다. 특히 흡수 스펙트럼의 3차원 재구성에 SMART 알고리즘을 적용하였다. 열전대와 CT-TDLAS로 모든 층의 온도를 비교한 결과 온도의 평균 상대오차가 19.7K로 정확하게 측정되었다.In order to use energy resources efficiently, accurate measurement of combustion gases is necessary. Measurement of the temperature and concentration of a target gas is possible with tunable laser absorption spectroscopy (TDLAS) technique. The TDLAS technique can be used to control and monitor combustion in industrial processes. The 3-dimensional temperature distribution of methane-air premixed flame was measured using the constructed computed tomography tunable diode laser absorption spectroscopy (CT-TDLAS) system. The 3-dimensional temperature distributions are measured by five layers of the 2-dimensional cell. The simultaneous multiplicative algebraic reconstruction technique (SMART) algorithm was adopted for reconstructing the absorption coefficients on the meshes. As a result of comparing the temperatures for all the layers using thermocouples and the CT-TDLAS technique, it was possible to accurately measure the average relative error of temperature as 19.7 K

EVALUATION OF 3D MEASUREMENT USING CT-TDLAS

In order to satisfy the requirements of high quality and optimal material manufacturing process, it is important to control the environment of the manufacturing process. Depending on these processes, it is possible to improve the quality of the product by adjusting various gases. With the advent of the TDLAS (Tunable laser absorption spectroscopy) technique, the temperature and concentration of the gases can be measured simultaneously. Among them, CT-TDLAS (Computed tomography-tunable diode laser absorption spectroscopy) is the most important technique for measuring the distributions of temperature and concentration across the 2-dimensional planes. In this study, suggest a 3-dimensional measurement to consider the irregular flow of supplying gases. Used the SMART (simultaneous multiplicative algebraic reconstruction technique) algorithm among the CT algorithms. Phantom data sets have been generated by the using Gaussian distribution method. It can be shown expected temperature and concentration distributions. The HITRAN database in which the thermo-dynamical properties and the light spectra of H2O are listed were used for the numerical test. The relative average temperature error ratio in the results obtained by the SMART algorithm was about 3.2% for temperature. The maximum error was 86.8K

Measurement Enhancement on Two-Dimensional Temperature Distribution of Methane-Air Premixed Flame Using SMART Algorithm in CT-TDLAS

In this study, the temperature distribution of the Methane-Air premixed flame was measured. In order to enhance the measurement accuracy of the CT-TDLAS (Computed tomography-tunable diode laser absorption spectroscopy), the SMART (simultaneous multiplicative algebraic reconstruction technique) algorithm has been adopted. Further, the SLOS (summation of line of sight) and the CSLOS (corrective summation of line of sight) methods have been adopted to increase measurement accuracies. It has been verified that the relative error for the temperatures measured by the thermocouples and calculated by the CT-TDLAS was about 10%

Large eddy simulation on the unsteady aerodynamic response of a road vehicle in transient crosswinds

A large eddy simulation method based on a fully unstructured finite volume method was developed, and the unsteady aerodynamic response of a road vehicle subjected to transient crosswinds was investigated. First, the method was validated for a 1/20-scale wind-tunnel model in a static aerodynamic condition; this showed that the surface pressure distributions as well as the aerodynamic forces and moments were in good agreement with wind-tunnel data. Second, the method was applied to two transient crosswind situations: a sinusoidal perturbation representing the typical length scale of atmospheric turbulence and a stepwise crosswind velocity corresponding to wind gusts. Typical transient responses of the aerodynamic forces and moments such as phase shifting and undershooting or overshooting were observed, and their dependence on the frequency and amplitude of the input perturbation is discussed. Thus, the utility and validity of the large eddy simulation was demonstrated in the context that such transient aerodynamic forces are difficult to measure using a conventional wind tunnel

Effects of homogeneous-heterogeneous reactions in flow of nanofluid between two stretchable rotating disks

The present study analyzes nanofluid flow over a two infinite rotating disk. A magnetic field addressed on momentum equation. An effect of homogeneous-heterogeneous reaction on the fluid flow is investigated. The relevant system of governing equations is transformed into ordinary differential equations by using Von Karman transformations. Homotopy approaches for different physical parameters are examined graphically on appropriate profile. For greater (S1) the radial, axial and azimuthal velocities are hiked. Energy of liquid enhances with increasing thermophoresis parameter Nt. Local Skin friction coefficient diminishes with higher Reynolds number at lower disk and opposite behavior at upper disk. Moreover concentration field elevates while increasing heterogeneous parameter

MHD convection of nanofluid in porous medium influenced by slanted Lorentz force

This paper presents a numerical investigation on magneto-hydrodynamics combined convection in a nanofluid-saturated porous 2-D cavity with different tilting angles of applied magnetic field and aspect ratios. The moving upper horizontal wall is heated uniformly. The temperature along the bottom wall is a constant cold temperature while the adiabatic condition is maintained at the vertical sidewalls. The finite volume method is applied to solve the system of non-dimensional equations. The pertinent parameters of the current study are Hartmann number (Ha), solid volume fraction (χ), Richardson number (Ri), the aspect ratio (Ar), Darcy number (Da), and the inclination angle of the magnetic field (γ). The slope of applied magnetic field affects the magnetic field intensity and the overall rate of heat transfer is augmented in the forced convection regime than the mixed convection regime. The mean Nusselt number raises on increasing of Ar for all considered Richardson numbers. In the presence of magnetic field, the rate of heat transfer is almost equal to the amplification of solid volume concentration when Ar = 0.25, whereas, it increases for Ar > 0.25 with the raise in the solid volume concentration. An increase in Hartmann number and Darcy number is insignificant on mean rate of heat transfer in the mixed convection regime at Ar ≤ 0.5