TFAWS Active Thermal Paper Session Thrust Performance Evaluation

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TFAWS Active Thermal Paper Session Thrust Performance Evaluation Of Chemical Rocket Engine By Thermal

TFAWS Active Thermal Paper Session Thrust Performance Evaluation Of Chemical Rocket Engine By Thermal And Fluid Dynamic Analysis For Exhaust Gas Flow Subjected To Cooling Karthik Naganathan, Lavanith Togaru Department of Mechanical Engineering, Kakatiya Institute of Technology & Science: Warangal, Telangana, India. Presented By Karthik Naganathan Thermal & Fluids Analysis Workshop TFAWS 2020 August 18 -20, 2020 Virtual Conference

TABLE OF CONTENTS • • • Problem statement Images of rocket nozzle model Nozzle

TABLE OF CONTENTS • • • Problem statement Images of rocket nozzle model Nozzle parameters and operating conditions Cooling system - Design requirements Effect of geometric parameters Flow analysis model Equations for modelling the flow Pressure, velocity and temperature plots Thrust characteristics Observations Conclusion Acknowledgment TFAWS 2020 – August 18 -20, 2020 2

PROBLEM STATEMENT • The chemical rocket engine is a mass based propulsion system. •

PROBLEM STATEMENT • The chemical rocket engine is a mass based propulsion system. • The exhaust gas is formed due to combustion of fuel and oxidizer and it is expelled through the nozzle with high temperature and pressure. • The thrust of chemical rocket is primarily dependent on mass flow rate, exit pressure and exit velocity. • The temperature of the exhaust gas does not actively contribute to the thrust of the rocket. • This papers studies the feasibility of conversion of exhaust gas temperature into exhaust gas pressure by cooling of exhaust gas. TFAWS 2020 – August 18 -20, 2020 3

IMAGES OF MODEL ROCKET NOZZLE TFAWS 2020 – August 18 -20, 2020 4

IMAGES OF MODEL ROCKET NOZZLE TFAWS 2020 – August 18 -20, 2020 4

IMAGES OF MODEL ROCKET NOZZLE TFAWS 2020 – August 18 -20, 2020 5

IMAGES OF MODEL ROCKET NOZZLE TFAWS 2020 – August 18 -20, 2020 5

IMAGES OF MODEL ROCKET NOZZLE TFAWS 2020 – August 18 -20, 2020 6

IMAGES OF MODEL ROCKET NOZZLE TFAWS 2020 – August 18 -20, 2020 6

NOZZLE PARAMETERS AND OPERATING CONDITIONS Parameter/ Operating condition Value/ Name Units Total length 5000

NOZZLE PARAMETERS AND OPERATING CONDITIONS Parameter/ Operating condition Value/ Name Units Total length 5000 mm Convergent inlet diameter 1750 mm Divergent exit diameter 4000 mm Throat diameter 1000 mm Convergent length 1500 mm Throat length 750 mm Divergent length 2750 mm Chamber pressure 70 bar Chamber temperature 1800 Celsius Mass flow rate 1970 Kg/s Exhaust gas Water vapour (Superheated) - Temperature drop while cooling 10 Celsius Method of cooling Two phase cooling system - TFAWS 2020 – August 18 -20, 2020 7

COOLING SYSTEM- DESIGN REQUIREMENTS • Heat removal rate should in order of 107 to

COOLING SYSTEM- DESIGN REQUIREMENTS • Heat removal rate should in order of 107 to 108 Watts. • The working fluid should be reusable. • The heat capacity and the density should be high. • The structural mass of the system should be minimum. • The freezing temperature should be very low. TFAWS 2020 – August 18 -20, 2020 8

EFFECT OF GEOMETRIC PARAMETERS • The area ratio of divergent to throat should be

EFFECT OF GEOMETRIC PARAMETERS • The area ratio of divergent to throat should be optimal to prevent normal shock formation in nozzle. • The area ratio of convergent is critical to achieve sonic velocity at throat. • The rate of change of area should not be drastic as it may lead to back pressure and reversed flow. • The overall size has significant effect on structural mass of the rocket. TFAWS 2020 – August 18 -20, 2020 9

FLOW ANALYSIS MODEL • The flow analysis is done using steady flow energy equation.

FLOW ANALYSIS MODEL • The flow analysis is done using steady flow energy equation. • There are 3 flow regimes in nozzle chamber. • The flow in the convergent section of the nozzle is modelled with subsonic flow condition. • The flow in the throat section of the nozzle is modelled with sonic flow condition. • The flow in the divergent section of the nozzle modelled with supersonic flow condition. • The exhaust gas cooling is done at throat of the nozzle. TFAWS 2020 – August 18 -20, 2020 10

EQUATIONS FOR MODELLING THE FLOW TFAWS 2020 – August 18 -20, 2020 11

EQUATIONS FOR MODELLING THE FLOW TFAWS 2020 – August 18 -20, 2020 11

Pressure vs. position - no cooling TFAWS 2020 – August 18 -20, 2020 12

Pressure vs. position - no cooling TFAWS 2020 – August 18 -20, 2020 12

Velocity vs. position - no cooling TFAWS 2020 – August 18 -20, 2020 13

Velocity vs. position - no cooling TFAWS 2020 – August 18 -20, 2020 13

Temperature vs. position - no cooling TFAWS 2020 – August 18 -20, 2020 14

Temperature vs. position - no cooling TFAWS 2020 – August 18 -20, 2020 14

Pressure vs. position - with cooling TFAWS 2020 – August 18 -20, 2020 15

Pressure vs. position - with cooling TFAWS 2020 – August 18 -20, 2020 15

Velocity vs. position - with cooling TFAWS 2020 – August 18 -20, 2020 16

Velocity vs. position - with cooling TFAWS 2020 – August 18 -20, 2020 16

Temperature vs. position - with cooling TFAWS 2020 – August 18 -20, 2020 17

Temperature vs. position - with cooling TFAWS 2020 – August 18 -20, 2020 17

THRUST CHARACTERISTICS NO COOLING CONDITION COOLING OF EXHAUST GAS • Higher exit pressure. •

THRUST CHARACTERISTICS NO COOLING CONDITION COOLING OF EXHAUST GAS • Higher exit pressure. • Lower density at throat. • Higher density at throat. • No significant effect on exit velocity because sonic velocity • It will lead to higher wall is maintained at throat. • It will lead to lower wall stresses. • For the given operating conditions a thrust of 2. 55 MN • For given operating conditions a thrust of 2. 54 MN is obtained TFAWS 2020 – August 18 -20, 2020 18

OBSERVATIONS • It is not possible to increase the pressure of the exhaust by

OBSERVATIONS • It is not possible to increase the pressure of the exhaust by decreasing its temperature. • When the temperature of the exhaust gas is decreased, the density of the fluid increases thus decreasing the velocity of the gas. • Excessive cooling lead to conversion of sonic flow to subsonic flow. • Internal energy is a low grade energy that is dependent on both temperature and pressure. It is observed for water vapour that internal energy slightly decreases with a large increase in pressure but it increases with an increase in temperature. • To achieve an isenthalpic flow in the nozzle, heat energy has to be added to the exhaust gas. • Addition of heat to the exhaust gas will improve the pressure and kinetic energy of the exhaust gas thereby improving the thrust generated by the rocket engine. TFAWS 2020 – August 18 -20, 2020 19

CONCLUSION • The thrust cannot be increased by the decreasing the temperature of the

CONCLUSION • The thrust cannot be increased by the decreasing the temperature of the exhaust gas. Instead the thrust generated can be increased by increasing the temperature. • The heating of exhaust gas is difficult but it can be achieved using high power systems such as plasma generators. • The effect on nozzle structure when exhaust gas is subjected to heating should be assessed. TFAWS 2020 – August 18 -20, 2020 20

ACKNOWLEDMENT • Magnus Holmgren (2020). X Steam, Thermodynamic properties of water and steam. (https:

ACKNOWLEDMENT • Magnus Holmgren (2020). X Steam, Thermodynamic properties of water and steam. (https: //www. mathworks. com/matlabcentral/fileexchange/9817 -xsteam-thermodynamic-properties-of-water-and-steam), MATLAB Central File Exchange. Retrieved August 7, 2020. This MATLAB function was used to determine state properties at various locations in the nozzle. • I would like to thank Mr. G. Vinod Kumar, Asst. Prof. , MED, KITSW and Ms. G. Sumithra, Asst. Prof. , MED, KITSW for their support in this project. TFAWS 2020 – August 18 -20, 2020 21

For further details contact: Karthik Naganathan nkarthikiyer 1998@gmail. com TFAWS 2020 – August 18

For further details contact: Karthik Naganathan nkarthikiyer 1998@gmail. com TFAWS 2020 – August 18 -20, 2020 22