To perform propulsion research through advanced laser diagnostics and is envisaged to serve as (i) centre for conducting academic research in IIST that would assist ISRO activities, (ii) national facility for performing advanced research and also as a (iii) national technological development centre for aerospace organizations.
The 1” x 1” (25mmx25mm) optically accessible chamber will be used to investigate the combustion and flame characteristics of hydrogen-oxygen / hydrogen-air reaction environments at high pressures and temperatures. The measurement techniques include species concentration and flow velocity fields using laser based diagnostic techniques like LIF and PIV in conjunction with wall heat flux measurements. |
The supersonic free jet facility is used to carry out cold flow mixing studies in supersonic flow using strut based injection into M=1.7 flow, cavity induced oscillations, flow through a double divergent nozzle and flow through vacuum ejector-diffuser system The maximum mass flow rate of the system corresponds to 0.5 kg/s at a stagnation pressure 5 bar absolute and stagnation temperature of 300 K |
The high pressure experimental facility is used for studying rocket jet fluid dynamics at supercritical conditions. A compound referred to as Fluoroketone is utilized for this purpose. Compared to the critical conditions of water, oxygen and hydrogen in that are extremely difficult to achieve, the critical conditions of the fluoroketone of Tcr = 169 oC and Pcr = 18 atm could be safely simulated in a laboratory. Moreover the compound is a fire suppressant and fluoresces and therefore PLIF technique could be applied for diagnostics. The key features of the facility are:
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The test rig is used for carrying out measurements involving spray cone angle, spray film length and thickness, droplet size and distribution, and spray droplet flow velocity using laser based diagnostic techniques. The cold flow water –air characterization could be conducted at a maximum flow rates of upto 3 lpm for water and 300 lpm for air |
The rig has a 450 mm dia x 1000 mm cylindrical water-cooled stainless steel chamber. The combustor can be used for combustion testing on fuels like gas oil and kerosene. It can be used for finding flame shape, flame stability, firing rate, flame radiation and exhaust species concentration. Water cooled temperature probes are provided which can be inserted through the windows at desired location and temperature at location can be found. Optical windows provide access for flow visualization |
The basic laser diagnostic facilities consist of (i) PIV Nd-YAG laser, (ii) Dye laser, (iii) Intensified CCD camera, (iv) PIV CCD camera, (v) High Resolution Wavemeter, (vi) External Image intensifier, (vii) Malvern spray particle analyzer and (viii)optical components and other accessories |
The study on injection of supercritical fluid into subcritical and supercritical environment involves a strong coupling between fluid dynamic and thermodynamic phenomena. Beyond the critical point, the fluid exists as single phase called as supercritical fluid with its properties that are entirely different from liquid and gases. The supercritical fluid does not possess surface tension and latent heat of evaporation. In this study, the transition of supercritical elliptical jet injected into subcritical environment as well as supercritical environment is investigated experimentally. Beyond the critical temperature, the axis switching is not observed. The investigation shows that pressure plays a major role in determining the thermodynamic transition in the elliptical jet. At larger pressure, the supercritical jet undergoes formation of droplets in the subcritical environment. However, for supercritical injection into supercritical environment, the gas-gas like mixing behavior is observed |
The inverse diffusion flame is referred to as the flame generated with an inner air jet surrounded by an outer fuel jet.It is combination of a premixed flame and diffusion flame that have a larger flammability range than premixed flame and is cleaner than the diffusion flame. This work investigated the flame structure associated with the IDF from the in terms of OH-PLIF images. A close inspection of the time average OH images revealed the flame structure distinctly in comparison with time averaged luminous image, for clarity, the OH image and flame luminous image was super positioned in Figure. The OH could be traced at a closer distance from the burner exit, and also showed that the reaction zone appeared as a very thin layer vicinity of burner exit |
Triplet injectors of different configurations that are used in PS4 engines are investigated using Mie scattering visualization technique. Flow pattern of these injectors for different flow rates are analysed. Images are obtained from two viewing planes, one perpendicular to the jet and the other parallel to it. These images are analysed and the angles of convergence and impingement angles are obtained using the image processing software. The images obtained from plane parallel to the jet revealed that for decreasing flow rates the impinging angle of the jet increases for almost all the injectors whereas the diverging angle decreases with decrease in flow rate |
The experimental methodology to perform droplet size distribution of Liquid Centered Swirl- Coaxial injector (LCSC) using simultaneous Planar Laser-Induced Fluorescence (PLIF) technique and MIE scattering is demonstrated. The fluid used for spray characterization was water with required quantities of the organic dye Rhodamine 6g for PLIF measurements. The injector performance was evaluated in terms of relative droplet size distribution and spray divergence angle. The droplet size distribution indicated that the relative SMD of droplets along the axial location of the spray was uniform throughout. It was also observed that improved performance in spray divergence angle could be achieved by recessing height of liquid passage with reference to the oxidizer | |
In a swirl injector, the liquid spreads out in the form of a conical sheet as soon as it leaves the nozzle. Design and performance of prefilming airblast or pressure swirl atomizers, is dependent on the spreading of the liquid into the thinnest possible sheet before encountering airblast action. Any increase in the thickness of the liquid sheet flowing over the atomizing lip will tend to increase the thickness of the ligaments which, upon disintegration, will then yield drops of larger size. The shape and disintegration characteristics of annular sheets formed by coaxial injectors are investigated in this study as functions of liquid flow rate. Variations in these parameters change the forces acting on the liquid sheet and, hence, lead to significant changes in the shape and disintegration behavior |
The objective of the study is to measure the flow field of an axisymmetric, isothermal jet emerging out of a circular tube at different flow conditions. The diagnostic method employed here is Particle Image Velocimetry (PIV). In the current studies the main air flow is seeded with olive oil droplets. The desired air flow rate is maintained in the feeding line by means of rotameter. After the rotameter, the air passed through a seeder and seeding particle of good concentration was embedded into the air flow. The air with seeding particles is then sent through the circular tube. The fluid flow with the tracer particles is illuminated by means of a frequency doubled, Nd:YAG PIV laser to visualize the particles. The velocity fields are measured by taking two images shortly after each other and calculating the distance individual particles travelled within this time by post processing the captured images. From the known time difference and the measured displacement the velocity is calculated. The obtained results will also be used for optimizing the PIV test facility |
Experiments are conducted to evaluate the effect of pylon on the mixing of secondary jet injection into supersonic mainstream flow at Mach 1.65. Two different pylons were investigated and the results are compared with those obtained by normal injection from a flat plate. The mixing studies are performed by varying the height of the pylon while keeping all other parameters the same. The study mainly focused on analyzing the area of spread and penetration depth achieved by different injection schemes based on the respective parameters. The measurements involved Mie scattering visualization and the flow features were analyzed using Schlieren images. The penetration height and spread area are the two parameters that were used for analyzing and comparing the performance of the pylons. It was observed that the secondary jet injection carried out from behind the big pylon resulted in maximum penetration and spread area of the jet as compared to the small pylon geometry. Moreover it was also evident that for obtaining maximum spreading and penetration of the jet, the same needs to be achieved at the injection location |
A study was conducted on supersonic flow of Mach number 1.65 over rectangular cavity of length-to-depth (L/D) ratio 3. Schlieren visualization revealed normal shock train like pattern in flow over the cavity. These shock structure were unsteady and oscillated longitudinally inside the test section over the cavity. The oscillating shock train was eliminated, as the blockage produced by shear layer and boundary layer thickening due to pressure recovery in cavity was reduced by offsetting the cavity aft wall. The shock train - shear layer coupling was observed to completely suppress the third and higher modes of cavity oscillations |
Dual bell nozzle is one of the feasible and cost effective techniques for altitude adaptation. Planar double divergent nozzle was designed to simulate and investigate the flow regimes similar to those inside the dual bell nozzle. The double divergent section with a rectangular cross section is designed for two different NPR’s. Measurements involved flow visualization using Schlieren technique and wall static pressure measurements. The flow transition between the two nozzles at the respective inflection points and the formation of recirculation region due to flow separation is analyzed in detail. Cold flow tests were performed on the double divergent nozzle in the over-expanded conditions to study the shock wave characteristics. The results obtained from the two independent double divergent nozzles are compared with those obtained from a single divergent nozzle of the same area ratio. From the experiments it was observed that inflection angle played a key role in defining the type of shock structures existing inside the double divergent nozzles |
A NanoscienceCentre was initiated in Department of Chemistry, Indian Institute of Space Science and Technologyto support and promote the advanced research on Nanoscience and technology. The centre’s long term objectives are: (1) Undertake challenging research projects in this area to meet the future requirements of ISRO, (2) Establish comprehensive research facilities under the same umbrella to attract intellectuals across the globe, (3) Mould high quality human resources to undertake future challenges, (4) To act as nodal centre, (5) To serveas a link between industry and academia in the country
Department of Avionics is establishing the center of excellence in Virtual Reality for various space and scientific applications. The development planned in three phases. The first phase consists of desktop VR lab which consists of high-end workstation with latest graphic capabilities, 3D monitors, 3D vision-pro glasses and application software’s such as Vizard, Blender, Google Sketch, Adobe Master Suit collection, 3ds Max and Maya. The facility will be upscale by creating an immersive studio type Virtual reality center in phase 2 and 3. The proposed facility will be supported by advanced haptic devices, sensors and force feedback systems for various real life application such as navigation, fly through etc. Some objectives to establish center of excellence in Virtual Reality at Department of Avionics, IIST Trivandrum are following:
The first phase of VR lab is accomplished in the year 2012-13. Since then a UG/PG elective course along with lab (using Vizard and Python) on Virtual Reality is being offered to 7th semester students. Every year UG/PG students carry out their internship project and Btech Project with existing facility. Work on procuring several Virtual Reality peripherals to augment their existing Desktop Virtual Reality setup is under way. These devices would be capable of being used with the Virtual Reality software development toolkit that is in place at the Desktop VR lab, WorldViz Vizard. These devices will be configured in such a way that they can be seamlessly integrated with the existing setup and can be driven from the workstations that are present in the lab. As of now one set of Virtual reality data gloves for interaction with objects in the virtual world is procured and added to existing facility.