Ground experimental simulation method of infrared radiation of high altitude aircraft’s surface

2018 ◽  
Vol 233 (8) ◽  
pp. 2980-2991
Author(s):  
Hao Wang ◽  
Jian Liu ◽  
Honghu Ji
Keyword(s):  
High Altitude ◽  
Radiation Intensity ◽  
Infrared Radiation ◽  
Simulation Method ◽  
Experimental Simulation ◽  
Scale Model ◽  
Surface Model ◽  
Wavelength Band ◽  
Temperature Range ◽  
Infrared Signature

It is difficult and costly to accurately measure the spectral and spatial distributions of the infrared radiation signature of a high altitude aircraft’s surface at relatively low temperatures. To reduce the experimental cost, simulated experimental measurement on the ground is usually made to measure its infrared signature. However, there are three main difficulties in the ground measurement: (1) it is difficult to simulate the temperature at high altitude which is much lower than the temperature near the ground; (2) it is difficult to accurately measure the infrared signature of a low temperature surface on the ground; and (3) it is difficult to measure the infrared signature of a prototype aircraft surface. To solve these problems, a ground experimental simulation method to obtain the infrared signature of a high altitude aircraft’s surface is developed, which makes it possible to use a scale model (scale factor M) at relatively higher temperature ( n times the temperature of the aircraft’s surface) to experimentally simulate the infrared signature of the actual aircraft’s surface. The results show that the integrated radiation intensity in the wavelength band between λ1 and λ2 of an original flying aircraft’s surface at a temperature range from T1 to T2 is equal to [Formula: see text] times the integrated radiation intensity in the wavelength band between λ1/ n and λ2/ n of the scale test surface model on the ground at a temperature range from nT1 to nT2.

scholarly journals Micro-Motion Dynamics and Shape Parameters Estimation Based on an Infrared Signature Model of Spatial Targets

Electronics ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 755 ◽  
Author(s):  
Dongya Wu ◽  
Huanzhang Lu ◽  
Bendong Zhao ◽  
Junliang Liu ◽  
Ming Zhao
Keyword(s):  
Radiation Intensity ◽  
Infrared Radiation ◽  
Estimation Method ◽  
Optimization Techniques ◽  
Parameters Estimation ◽  
Geometrical Shape ◽  
Infrared Signature ◽  
Micro Motion ◽  
Periodic Fluctuations ◽  
Motion Dynamics

Infrared imaging is widely applied in the discrimination of spatial targets. Extracting distinguishable features from the infrared signature of spatial targets is an important premise for this task. When a target in outer space experiences micro-motion, it causes periodic fluctuations in the observed infrared radiation intensity signature. Periodic fluctuations can reflect some potential factors of the received data, such as structure, dynamics, etc., and provide possible ways to analyze the signature. The purpose of this paper is to estimate the micro-motion dynamics and geometry parameters from the observed infrared radiation intensity signature. To this end, we have studied the signal model of the infrared radiation intensity signature, conducted the geometry and micro-motion models of the target, and we proposed a joint parameter estimation method based on optimization techniques. After analyzing the estimation results, we testified that the parameters of micro-motion and geometrical shape of the spatial target can be effectively estimated by our estimation method.

Numerical evaluation of the exhaust-direction effects on plume flow and helicopter infrared radiation under hover and cruise statuses

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Zongyao Yang ◽  
Yong Shan ◽  
Jingzhou Zhang
Keyword(s):  
Radiation Intensity ◽  
Infrared Radiation ◽  
Design Methodology ◽  
Main Rotor ◽  
Content Type ◽  
Exhaust Plume ◽  
Ir Signature ◽  
Plume Flow ◽  
The Impact ◽  
Rotational Direction

Purpose This study aims to investigate the effects of exhaust direction on exhaust plume and helicopter infrared radiation in hover and cruise status. Design/methodology/approach Four exhaust modes are concerned, and the external flow field and fuselage temperature field are calculated by numerical simulation. The infrared radiation intensity distributions of the four models in hovering and cruising states are computed by the ray-tracing method. Findings Under the hover status, the exhaust plume is deflected to flow downward after it exhausts from the nozzle exit, upon the impact of the main-rotor downwash. Besides, the exhaust plume shows a “swirling” movement following the main-rotor rotational direction. The forward-flight flow helps prevent the hot exhaust plume from a collision with the helicopter fuselage generally for the cruise status. In general, the oblique-upward exhaust mode provides moderate infrared radiation intensities in all of the viewing directions, either under the hover or the cruise status. Compared with the hover status, the infrared radiation intensity distribution alters somewhat in cruise. Originality/value Illustrating the influences of exhaust direction on plume flow and helicopter infrared radiation and the differences of helicopter infrared radiation under hover and cruise statuses are identified. Finally, an appropriate exhaust mode is proposed to provide a better IR signature distribution.

scholarly journals Analysis of Infrared Radiation Intensity by Water-Mist Spraying in Ship Exhaust System

2021 ◽  
Vol 2112 (1) ◽  
pp. 012019
Author(s):  
Zhongke Sun ◽  
Zhen Wang ◽  
Zhongwei Chen ◽  
Zhihua Liu ◽  
Mo Liu ◽  
...  
Keyword(s):  
Radiation Intensity ◽  
Infrared Radiation ◽  
Exhaust System ◽  
Water Mist ◽  
Mist Cooling

Abstract The infrared radiation intensity in 3~5μm of conventional ship exhaust system are so severe [1] that can be easily captured by detector. Therefore, it’s necessary to take measure like spraying water mist to decrease temperature of exhaust system in order to decrease infrared radiation intensity. In this paper, the calculation of infrared radiation intensity of conventional ship exhaust system with water-mist spraying will be given. The results show that the average and maximum infrared radiation intensity of the exhaust system can be reduced by 90.3% and 95.7% after water mist cooling.

Study of Tunnel Water Detection through Infrared Acquisition Technology Based on 3D Trend Analysis

2013 ◽  
Vol 838-841 ◽  
pp. 1370-1380
Author(s):  
Shu Hao Zhang ◽  
Ya Wei Wang
Keyword(s):  
Trend Analysis ◽  
Radiation Field ◽  
Radiation Intensity ◽  
Infrared Radiation ◽  
Tunnel Construction ◽  
Water Detection ◽  
Visualization Software ◽  
Comparison And Analysis

The study discusses a revised method of water detection through infrared acquisition technology. In the case of Xianghe tunnel construction, the authors built 3D infrared radiation field functions through 3D trend analysis. The separately calculated radiation intensity trend values and outliers were processed by the visualization software, Voxler, and transformed into 3D distribution graphs for further comparison and analysis. The result indicates that the technique and method applied in this article successfully eliminate the random interference and realize the detection of aquifer.

scholarly journals Hybrid Method of Modal Analysis and Laser Shock Scanning to Visualize the Pyroshock Propagation in a Tension Joint

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Yong-Woon Kim ◽  
Jae-Kyeong Jang ◽  
Jung-Ryul Lee ◽  
Hak-Seong Gim
Keyword(s):  
Modal Analysis ◽  
Hybrid Method ◽  
Response Spectrum ◽  
Near Field ◽  
Low Frequency ◽  
Simulation Method ◽  
Experimental Simulation ◽  
Laser Shock ◽  
Simulation Results ◽  
Tension Joint

The use of pyrodevices in the aerospace industry has been increasing because of their ability to implement separation missions with a small weight, for example, space launchers, spacecrafts, and missiles. During operation, pyrodevices generate pyroshock, which causes failures of electronic devices. Recently, a pyroshock simulation method using laser shock has been developed to evaluate the risk of pyroshock before flight mission. However, depending on the structure, the laser shock showed some difficulty simulating pyroshock in the low-frequency regime accompanying vibration. Therefore, in this study, we developed a hybrid method of numerical modal analysis and laser shock-based experimental simulation to visualize the pyroshock propagation in all the relevant frequency regimes. For the proof of concept of the proposed method, we performed experiments of explosive bolt-induced shock and pyrolock-induced shock in the open-box-type tension joint and compared the hybrid simulation results with actual pyroshock. From the results, we obtained the simulated time-domain signal with an averaged peak-to-peak acceleration difference (PAD) of 11.2% and the shock response spectrum (SRS) with an averaged mean acceleration difference (MAD) of 28.5%. In addition, we were able to visualize the simulation results in the temporal and spectral domains to compare the pyroshock induced by each pyrodevice. A comparison of the simulations showed that the pyrolock had an impulse level of 1/12 compared to the explosion bolt. In particular, it was confirmed that the pyrolock-induced shock at the near field can cause damage to the electronic equipment despite a smaller impulse than that of the explosive bolt-induced shock. The hybrid method developed in this paper demonstrates that it is possible to simulate pyroshock for all the frequency regimes in complex specimens and to evaluate the risk in the time and frequency domain.

Nozzle dimension design for aircraft engine infrared signature and thrust active control using MOEA/D

2020 ◽  
Vol 234 (15) ◽  
pp. 2133-2138
Author(s):  
Yu Zhao ◽  
Shijie Zheng
Keyword(s):  
Nozzle Exit ◽  
Infrared Radiation ◽  
Exhaust System ◽  
Aircraft Engine ◽  
Radiation Energy ◽  
Diameter Ratio ◽  
Rear Side ◽  
Military Aircraft ◽  
Infrared Signature ◽  
Aircraft Survivability

Aircraft infrared signature is one of the most important properties for the military aircraft survivability. In terms of military aircraft, the exhaust system is the most significant infrared radiation source. The exhaust system accounts for more than 90% of the aircraft infrared radiation, and that the exhaust nozzle contributes the most significant infrared radiation of the whole radiation energy provided by the exhaust system from the rear aspect. Low detectionable feature for military aircraft has attracted more importance to promote aircraft survivability via reducing infrared signature. The alteration of nozzle exit area affects an aircraft engine performance; meanwhile, it severely influences the engine infrared signature radiation from the rear side. The present paper is mainly focused on searching an appropriate group of nozzle exit diameter and throat to exit diameter ratio, which can reduce infrared signature radiation while cutting down the loss of thrust. Hence, objectives involve two aspects: one is minimum infrared signature level, and the other is minimum thrust loss. The multi-objective evolutionary algorithm based on decomposition has been employed to solve this bi-objective optimization problem. The optimization results illustrate that dimension selection range and throat to exit diameter ratio exert more important effect on the thrust loss and infrared signature level. Furthermore, the thrust plays significant role for deciding nozzle exit diameter and throat diameter.

scholarly journals Assessment of Roughness Length Schemes Implemented within the Noah Land Surface Model for High-Altitude Regions

2014 ◽  
Vol 15 (3) ◽  
pp. 921-937 ◽  
Author(s):  
Donghai Zheng ◽  
Rogier van der Velde ◽  
Zhongbo Su ◽  
Martijn J. Booij ◽  
Arjen Y. Hoekstra ◽  
...  
Keyword(s):  
Heat Flux ◽  
High Altitude ◽  
Land Surface ◽  
Land Surface Model ◽  
Surface Heat ◽  
Heat Fluxes ◽  
Surface Model ◽  
Surface Heat Fluxes ◽  
Noah Land Surface Model ◽  
Better Than

ABSTRACT Current land surface models still have difficulties with producing reliable surface heat fluxes and skin temperature (Tsfc) estimates for high-altitude regions, which may be addressed via adequate parameterization of the roughness lengths for momentum (z0m) and heat (z0h) transfer. In this study, the performance of various z0h and z0m schemes developed for the Noah land surface model is assessed for a high-altitude site (3430 m) on the northeastern part of the Tibetan Plateau. Based on the in situ surface heat fluxes and profile measurements of wind and temperature, monthly variations of z0m and diurnal variations of z0h are derived through application of the Monin–Obukhov similarity theory. These derived values together with the measured heat fluxes are utilized to assess the performance of those z0m and z0h schemes for different seasons. The analyses show that the z0m dynamics are related to vegetation dynamics and soil water freeze–thaw state, which are reproduced satisfactorily with current z0m schemes. Further, it is demonstrated that the heat flux simulations are very sensitive to the diurnal variations of z0h. The newly developed z0h schemes all capture, at least over the sparse vegetated surfaces during the winter season, the observed diurnal variability much better than the original one. It should, however, be noted that for the dense vegetated surfaces during the spring and monsoon seasons, not all newly developed schemes perform consistently better than the original one. With the most promising schemes, the Noah simulated sensible heat flux, latent heat flux, Tsfc, and soil temperature improved for the monsoon season by about 29%, 79%, 75%, and 81%, respectively. In addition, the impact of Tsfc calculation and energy balance closure associated with measurement uncertainties on the above findings are discussed, and the selection of the appropriate z0h scheme for applications is addressed.

scholarly journals Research on the Characteristics of Infrared Radiation Spectra at Zigong Acupoint within Menstrual Cycle of Healthy Female

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Meng Qin ◽  
Si-qi Ma ◽  
Zhi-ming Huang ◽  
Xue-yong Shen ◽  
Jian-zi Wei
Keyword(s):  
Menstrual Cycle ◽  
Radiation Intensity ◽  
Infrared Radiation ◽  
Statistical Difference ◽  
Radiation Spectrum ◽  
Control Point ◽  
Control Points ◽  
Total Radiation ◽  
Healthy Female ◽  
The Right

The purpose of this study was to observe the characteristics of infrared radiation spectrum of Zigong acupoint (EX-CA1) within the menstrual cycle of healthy female. We used highly sensitive infrared radiation spectrum detection system and phase-locked amplification technology to detect and analyse the infrared radiation spectrum from 1.5μm to 18μm of 32 healthy female before, during, and after menstruation at EX-CA1 and control points. The results showed that the total radiation intensity of left EX-CA1 was significantly higher than that of left control point (P<0.05) at the whole menstrual cycle, and the difference between right EX-CA1 and right control points was statistically significant before and after menstruation (P<0.05), no statistical difference during menstruation. Previous studies found that the radiation near 15μm was correlated with glucose metabolism. The results of this study showed that there were statistical differences in 10 wavelengths between left EX-CA1 and left control point from 14μm to 18μm, and there were statistical differences in 3 wavelengths on the right side (P<0.05). The left side is more prominent than the right side. The infrared radiation intensity of EX-CA1 decreased gradually with the change of cycle rhythm within menstrual cycle, but there was no statistical difference in this trend. There was no statistical difference in total radiation intensity between the right and left side of EX-CA1. Compared with the control points, the number of different wavelengths between left EX-CA1 and left control point during menstruation was significantly larger than that between right EX-CA1 and right control point (P<0.001). The results indicated that the energy of EX-CA1 was higher than control points. There was no difference in the radiation intensity between the right and left sides of EX-CA1 but there was acupoint laterality compared with nonacupoints. There was no significant rhythmic change in infrared radiation intensity of EX-CA1 during the menstrual cycle.

scholarly journals Stress-constrained optimization using graded lattice microstructures

2020 ◽  
Author(s):  
Dilaksan Thillaithevan ◽  
Paul Bruce ◽  
Matthew Santer
Keyword(s):  
Constrained Optimization ◽  
Optimization Problems ◽  
Full Scale ◽  
Von Mises Stress ◽  
Scale Model ◽  
Stress Constraint ◽  
Surface Model ◽  
Linear Superposition ◽  
Deformation Problem ◽  
Graded Structures

Abstract In this work, we propose a novel method for predicting stress within a multiscale lattice optimization framework. On the microscale, a scalable stress is captured for each microstructure within a large, full factorial design of experiments. A multivariate polynomial response surface model is used to represent the microstructure material properties. Unlike the traditional solid isotropic material with a penalization-based stress approach or using the homogenized stress, we propose the use of real microscale stress components with macroscale strains through linear superposition. To examine the accuracy of the multiscale stress method, full-scale finite element simulations with non-periodic boundary conditions were performed. Using a range of microstructure gradings, it was determined that 6 layers of microstructures were required to achieve periodicity within the full-scale model. The effectiveness of the multiscale stress model was then examined. Using various graded structures and two load cases, our methodology was shown to replicate the von Mises stress in the center of the unit lattice cells to within 10% in the majority of the test cases. Finally, three stress-constrained optimization problems were solved to demonstrate the effectiveness of the method. Two stress-constrained weight minimization problems were demonstrated, alongside a stress-constrained target deformation problem. In all cases, the optimizer was able to sufficiently reduce the objective while respecting the imposed stress constraint.

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