The Liquid Propulsion Systems Centre (LPSC) is a research and development centre functioning under Indian Space Research Organisation. It has two units located at Valiamala, in Thiruvananthapuram of Kerala, and Bengaluru of Karnataka. LPSC is augmented by ISRO Propulsion Complex at Mahendragiri of Tamil Nadu.LPSC is engaged in development of liquid and cryogenic propulsion stages for launch vehicles and auxiliary propulsion systems for both launch vehicles and satellites. Activities related to liquid propulsion stages, cryogenic propulsion stages and control systems for launch vehicles and spacecraft is done at Thiruvananthapuram. Precision fabrication facilities, development of transducers and integration of satellite propulsion systems are carried out at Bangalore. The developmental and flight tests along with assembly and integration are done at ISRO Propulsion Complex, Mahendragiri in Tamil Nadu.The development of liquid propellant stages for PSLV, control systems for SLV-3, ASLV, PSLV and GSLV, satellite propulsion systems including those for INSAT and IRS and production of pressure transducers are done by the LPSC for India. The LPSC has developed indigenous cryogenic upper stage for Geosynchronous Satellite Launch Vehicle (GSLV) which was successfully test fired by ISRO on 4 August 2007.LPSC's current director is Dr. V Narayanan. He succeeded Mr. S Somnath in January, 2018 after which Shri S Somnath was appointed as Director of VSSC.
In this paper, the repeatability of laser powder bed fusion (LPBF) process during the additive manufacturing (AM) of Inconel Alloy 718 (IN718) is thoroughly investigated. The main objective is to study batch to batch consistency with respect to repeatably and reproducibility of the AM process and its effect on mechanical and microstructural characteristics. This study further compares properties of LPBF IN718 alloy with its wrought counterpart. The results indicate high repeatability in microstructural characteristics, such as grain size and phase distribution, across multiple printing batches of Inconel Alloy 718. Microscopic analysis showed presence of long columnar grains parallel to build direction and fine equiaxed grains perpendicular to it. Additionally, evaluations of mechanical properties including yield strength (YS), ultimate tensile strength (UTS), and elongation at fracture (ef) generally show little variation across various batches, demonstrating excellent repeatability and reproducibility. YS and UTS were observed to be 1200 and 1400 MPa, respectively, for all samples with near isotropy. On the other hand, elongation to failure exhibited anisotropy with orientation parallel to build direction having higher elongation (> 20
This paper investigates the combined effect of heat treatment and cold working on 12Cr21 duplex stainless steel. Five different temperatures were selected for solution treatment in the range of 900–1080 °C with a cold reduction of 15 and 30
Thrust chamber of liquid rocket engine consists of two shells to form the cooling passage for regenerative cooling. Inner shell consists of several channels and ribs for the coolant to flow. The inner and outer shells of Thrust Chamber are joined together by brazing. Conventionally, brazing filler material (BFM) is tack welded on the outer shell, which melts at the brazing temperature to facilitate the joining. The parts have to be rotated during brazing in Rotary Vacuum Brazing Furnace (RVBF) to avoid accumulation of BFM due to gravity. In the current study an alternate brazing technique is attempted in which coatings are provided on inner and outer shells in place of BFM, which react at a specific temperature to form in-situ braze alloy. This type of process is widely referred as Transient Liquid Phase bonding (TLP), Diffusion brazing (DB), Contact reactive brazing, etc. Fluidity of the in-situ formed braze alloy is minimal and there is a real scope of carrying out static brazing of components using coatings instead of complex RVBF. To demonstrate the static brazing technology, brazing trial was carried out on a simulator hardware. Hardware was brazed at 1000 °C using a Vacuum compression furnace and aged at 510 °C. Post brazing the hardware was subjected to burst test and hardware failed at a pressure of 878 bar.
1D heterogeneous dual-phase model of a cryogenic liquid Hydrogen (LH2) propellant tank pressurization system was developed. Simulations were carried out using SINDA/FLUINT version 6.3, a finite difference, lumped parameter tool, to determine the quantity of gaseous Helium (GHe) for pressurization of the fuel tank in the cryogenic upper stage of a rocket. As there was no feasibility of establishing a lab-level twin of the total system, the model was validated on a sub-system level with data from other flight measurements. The design strategy was to identify the worst-case scenario so that the proposed active pressurization system would cater to most adversities in flight. The non-dimensional GHe mass and time required for pressurization were determined to be in the range of m* = (0.058 to 0.145) and Δτ = 0.18 × 10–6 to 0.38 × 10–6 respectively. Post-flight simulations indicated that m* = 0.1 of GHe was required to pressurize the tank by ΔP = 0.174 in Δτ = 0.32 × 10–6
Dissimilar metal joining of different classes of superalloys such as nickel-based superalloy XH60BT and cobalt-based superalloy KC20WN has unique potential in high-performance aerospace applications, such as aero-engine transition liners and rocket engine nozzles. In this study, dissimilar weld joints XH60BT and KC20WN were created using gas tungsten arc (GTA) and electron beam welding (EBW) methods. Two grades of filler metals, Haynes 230 and KC20WN, were used during GTA welding to determine the optimal filler metal for the dissimilar combination. The weld joints underwent extensive nondestructive examinations, metallurgical analyses using techniques such as SEM, XRD, and EBSD, and mechanical characterizations, assessing hardness and tensile properties at room and elevated temperatures of 900-1200 °C. In GTA welding, the KC20WN filler wire achieves tensile strength comparable to XH60BT alloy with 33
