Manufacturing Technology Today

N. Kishore Nath ¹

Affiliations
1 Advanced Systems Laboratory, Kanchanbagh, Hyderabad, IN

Abstract

The ablative liners are used to protect the nozzle structural members from the severe thermal environment in solid rocket nozzles. The ablative liners are made with carbon phenolic prepreg flakes by compression moulding process. The objective of this work is to demonstrate the optimization of process parameters of compression moulding process to achieve better erosion resistance using Taguchi's robust design methodology. In this method four control factors Pressure applied, Charge Temperature, Tool Pre heat Temperature, Number of charges, were investigated for the compression moulding process. The presented work was to study the cogency and acceptability of Taguchi's methodology in manufacturing of ablative liners. The quality characteristic identified was erosion rate. Experiments carried out using L₉ Orthogonal array with four different levels of control factors. The test results were analyzed using smaller the better criteria for S/N ratio in order to optimize the process. The experimental results were analyzed conformed and successfully used to achieve the minimum erosion rate of the ablative liners. The enhancement in performance of the ablative liners were observed by carrying out the oxy acetylene tests. The influence of erosion rate on the performance of ablative liners was verified by ground firing test.

Keywords

Ablative Liners, Carbon Fabric, Phenolic Resin, Prepreg, Erosion Rate, Taguchi’s Robust Design Methodology, Orthogonal Array.

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N. Kishore Nath ¹, B. Dinesh Kumar ¹

Affiliations
1 Advanced Systems Laboratory, Kanchanbagh, Hyderabad, IN

Abstract

Vectoring tests are carried out on each flex nozzle system of a rocket motor to verify the performance of flex seal using Electro Mechanical actuators, mirror image sensors and electronic controller. These tests are done for acceptance of the flex nozzle control system in the missile. The flex nozzle controls are tested for sine, ramp, frequency, response commands. During the tests the Command, Pitch, Average, Main Voltages are recorded using DAC. The flex nozzle system is integrated to the pressure chamber in horizontal condition and the Electro Mechanical actuators and mirror image sensors are assembled to the flex nozzle systems. The Electro Mechanical actuators are connected to the battery or 70V power supply to operate the actuators. Then the vectoring tests are performed using the Electro Mechanical actuators. LVDT'S are mounted on nozzle for displacement measurement. The chamber is pressurized pneumatically up to 2 bar.

Keywords

Flex Nozzle System, Electro Mechanical Actuators, Vectoring Tests, Digital Controllers.

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N. Kishore Nath ¹, P. Mallesam ²

Affiliations
1 Advanced Systems Laboratory, Kanchanbagh, Hyderabad, IN
2 Sri Indu College of Engg., Sheriguda, Ibrahimpatnam, R.R. (Dist), IN

Abstract

Solid rocket motor generates thrust by converting pressure energy to kinetic energy of propulsion in the nozzle. The structural steel members of nozzle should be protected from hot gases by highly erosion resistant thermal liners. Ablative composite liners made up of rayon carbon fabric and phenolic resin. Divergent liner thickness should be as minimum os possible at the same time, it should be more erosion resistant. The erosion resistant due to hot gases can be increased by fabricating the liner in such a way that the flame only touches the edge of the composite ply of liner and liner has more density. This can be achieved by tape winding of composite prepreg tapes at zero degrees on tapered metal mandrel using tape winding machine followed by autoclave curing. This paper gives the details of prepreg, tape winding, autoclave curing and NDT of the ablative liner.

Keywords

Rayon Carbon Fabric, Phenolic Resin, Prepreg, Tape Winding, Autoclave Curing.

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