1. 1 2/10/2005Thrust Chamber Assembly Concept Design Review Components of TCA Injector Chamber Nozzle

2. 2 2/10/2005Thrust Chamber Assembly Concept Design Review The first step in the design was to pick propellants –LOX – propylene chosen for several reasons Customer has experience and access Allow for partial self pressurization of propellant tanks The mixture ratio is specified by CSULB based on the ratio that will give the best operability = 2.27. This allows for the propellant tanks to empty at the same rate A chamber pressure must be chosen –300 psi was chosen by the customer. Current tanks can handle 450 psi  300 psi chamber pressure after losses Cooling by passive means is possible (No dump or regenerative cooling required) Design Process

3. 3 2/10/2005Thrust Chamber Assembly Concept Design Review With the information available we run the NASA thermochemistry code to obtain some useful data: –Chamber Temp (T c ) = 6341 R –C* = 6044 ft/s –Exit pressure (p e ) = 5.66 psi –Exit velocity (v e ) = 9627.8 ft/s –Cf vac = 1.593 –Specific heat ratio γ = 1.1398 –Molecular weight = 21.313 –Isp vac = 327.6 s Design Process

4. 4 2/10/2005Thrust Chamber Assembly Concept Design Review With this data we can continue with the design of the engine. We would like to use the equation that relates mass flow rate to force and Isp so first we need C f at sea level, and then Isp at sea level and then finally mass flow rate through the engine. From NASA code Design parameters From NASA code Design parameter Design Process

5. 5 2/10/2005Thrust Chamber Assembly Concept Design Review We know our O/F ratio so we can then split the mass flow into fuel and oxidizer: Where r is the mixture ratio The throat area is found with: We choose a contraction ratio of 2 to help with combustion stability Design Process

6. 6 2/10/2005Thrust Chamber Assembly Concept Design Review We use the design parameter L* to find the size of the combustion chamber. We used an L* of 42.5 in because it has worked successfully in the past with RP-1. This is the volume needed Length of converging section with θc the converging half angle Volume that the converging section makes Use a cylinder to make the rest of the volume Design Process

7. 7 2/10/2005Thrust Chamber Assembly Concept Design Review Injector design pressure loss is 70 psi. We use.2*Pc = 60 psi for the drop across the orifices Area for injection is found with the pressure drop from the manifold to the chamber with: Cd is discharge coefficient =.80 Design Process We need to select hole sizes based on drill bits that can be purchased. By selecting the number of orifices that we want we can find the hole sizes that we need. Going back we can find the new mass flows and actual O/F.

8. 8 2/10/2005Thrust Chamber Assembly Concept Design Review Design Requirements – Chamber L* = 42.5 in Should withstand heat flux for burn time Should withstand any transient pressure Should not be overly complicated (Cheap to build) Cannot use regenerative cooling because of lack of pressure budget Use ablative liner and film cooling or O/F bias. Convergence ratio of 2 Need to be able to flange onto injector

9. 9 2/10/2005Thrust Chamber Assembly Concept Design Review Design Specs - Chamber Chamber Diameter = 3.69 in Length of chamber = 20.73 in Length of converging section ≈.64 in Diameter of throat = 2.61 in

10. 10 2/10/2005Thrust Chamber Assembly Concept Design Review Current Chamber Design Put drawing here

11. 11 2/10/2005Thrust Chamber Assembly Concept Design Review Design Requirements – Nozzle Expansion ratio = 8 75% bell to assist in weight reduction Manufacturing must be taken into consideration –Conical nozzle used to be cheaper to manufacture –CNC manufacturing has reduced cost of bell nozzle Uncooled NASA Dryden

12. 12 2/10/2005Thrust Chamber Assembly Concept Design Review Design Specs - Nozzle Length of nozzle –8.91 in (15° cone) –7.13 in (80% bell) 75% Bell –Lower Weight –Better Performance Bell Nozzle on Pump-Fed LRE

13. 13 2/10/2005Thrust Chamber Assembly Concept Design Review Current Nozzle Design

14. 14 2/10/2005Thrust Chamber Assembly Concept Design Review Design Requirements - Injector By far the most complicated part of design ΔP = 70 psi Shouldn’t melt or scorch Provide combustion stability No inter-propellant seals Total flow rate = 8.45 lbm/s Ox flow rate = 5.87 lbm/s Fuel Flow rate = 2.58 lbm/s

15. 15 2/10/2005Thrust Chamber Assembly Concept Design Review O-F-O Impinging Injector Injector provides for propellant mixing by impinging jets. Two oxidizer jets impinge on one fuel jet. OOF Fan

16. 16 2/10/2005Thrust Chamber Assembly Concept Design Review O-F-O Injector Well known design process Better performance compared to pintle Allows for O/F biasing against wall and film cooling Propellants are well suited for this option –SG propylene =.5 –SG LOX = 1.14 –O/F = 2.27

17. 17 2/10/2005Thrust Chamber Assembly Concept Design Review Injector Sizing 18 – triplets 18 film cooling elements Oversize outboard oxidizer element to ensure jets stay away from the wall Impingement point length/ diameter of orifice should be ~ 5 Bore length/diameter of orifice should be > 3.5 to ensure Cd =.80 Manifolds – 10*area of orifices they feed

18. 18 2/10/2005Thrust Chamber Assembly Concept Design Review Injector Concept

19. 19 2/10/2005Thrust Chamber Assembly Concept Design Review Injector Concept

20. 20 2/10/2005Thrust Chamber Assembly Concept Design Review Injector Concept Put the picture here

21. 21 2/10/2005Thrust Chamber Assembly Concept Design Review Injector Performance Analysis With these sizes: Stream Lengths Bore Lengths

22. 22 2/10/2005Thrust Chamber Assembly Concept Design Review Injector Lengths

23. 23 2/10/2005Thrust Chamber Assembly Concept Design Review Manifold Sizes

24. 24 2/10/2005Thrust Chamber Assembly Concept Design Review Manifold Sizes

25. 25 2/10/2005Thrust Chamber Assembly Concept Design Review Manifold Sizes A ox,in =.08165 in 2 A ox,out =.01437 in 2 A fuel =.01452 in 2 A film =.00226 in 2 Flow Area/ Injection Area Ox in = 2.296 Ox out = 7.738 Fuel = 9.043 Film = 33.186

26. 26 2/10/2005Thrust Chamber Assembly Concept Design Review Injector performance Velocities: –Ox = 88.35 ft/s –Fuel = 120.45 ft/s Momenta –Ox_out = 222 lb-in/s 2 –Ox_in = 210 lb-in/s 2 –Fuel = 224 lb-in/s 2 0.9911 : 1.0000 : 0.9375

27. 27 2/10/2005Thrust Chamber Assembly Concept Design Review Injector Fill Times Volumes Vox = 7.13508 in 3 Vf =.26875 in 3 Volumetric flows Qox = 142 in 3 /s Qf = 118.5 in 3 /s Fill times t ox =.05 sec t fuel =.002 sec

28. 28 2/10/2005Thrust Chamber Assembly Concept Design Review Combustion Stability Stable Unstable

29. 29 2/10/2005Thrust Chamber Assembly Concept Design Review Current Concept Summary Injector: O-F-O Injector Chamber: Ablative Lining Nozzle: 80% Bell Picture here

30. 30 2/10/2005Thrust Chamber Assembly Concept Design Review Numbers Summary O/F2.2729 Pc300psi F2200lbf ε8 Tc6340R c*6044ft/s Pe5.66psi ve9628ft/s Cf)vac1.593 γ1.1398 MW21.313lb/lbmole Ivac327.6s Iopt299.2s L*42.5in εc2 Pc/Pa20.41 Cf1.44207 η0.95 Isp257.35s c8280ft/s

31. 31 2/10/2005Thrust Chamber Assembly Concept Design Review Numbers mdot8.4519lb/s mo5.8695lb/s mf2.5824lb/s Dc3.692inChamber Ac10.706in^2 Dt2.6107inThroat At5.353in^2 De7.3841inExit Ae42.82in^2 Lc20.72inLength of chamber

32. 32 2/10/2005Thrust Chamber Assembly Concept Design Review Numbers ΔP60psiinjector pressure drop ρ lox0.0412lb/in^3density lox ρ fuel0.0218lb/in^3 Cd0.8 discharge coeff Dfilm0.031infilm orifices Dox,out0.0781inoutside orifices Dox,in0.076ininside orifices Dfuel0.0785infuel orifices Aox0.167887in^2 Afuel0.100703in^2 Vox1060in/s88.33333ft/s Vfuel1445in/s120.4167ft/s mom_ox_o222lb-in/s mom_ox_in210lb-in/s mom_f224lb-in/s

33. 33 2/10/2005Thrust Chamber Assembly Concept Design Review Numbers ac49259in/s4104.917ft/s f1t7821Hz f2t12974Hz f3t17845Hz f1r16276Hz f2r29800Hz Df/Vf5.40E-05s

34. 34 2/10/2005Thrust Chamber Assembly Concept Design Review Adiabatic Flame Temperature vs. O/F Ratio

35. 35 2/10/2005Thrust Chamber Assembly Concept Design Review Cstar vs. O/F Ratio

36. 36 2/10/2005Thrust Chamber Assembly Concept Design Review Ivac vs. O/F Ratio

37. 37 2/10/2005Thrust Chamber Assembly Concept Design Review Thrust Coefficient vs. O/F Ratio