init

thrust.jl

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+using Unitful
+using DataFrames
+using Plots
+using UnitfulRecipes
+using Roots
+using CSV
+
+
+# Tank https://www.amazon.com/Empire-Paintball-BASICS-Pressure-Compressed/dp/B07B6M48SR/
+V = 90u"inch^3"
+P0 = 4500.0u"psi"
+Wtank = 2.3u"lb"
+Pmax = 100u"psi"
+
+Wsolenoid = 1.5u"kg"
+
+# Params
+d_nozzle = (1 // 16) * u"inch"
+a_nozzle = (pi / 4) * d_nozzle^2
+Poutmax = 800u"psi"
+
+# Universal Stuff
+P_amb = 1u"atm"
+γ = 1.4
+R = 287.05u"J/(kg * K)"
+T = 300u"K"
+
+# Setting up while loop
+t = 1.0u"s"
+P = P0 |> u"Pa"
+M = V * (P / (R * T)) |> u"kg"
+df = DataFrame(Thrust = 0.0u"N", Pressure = P, Time = t, Mass = M)
+ts = 0.001u"s"
+while M > 0.01u"kg"
+    # while t < 30u"s"
+    # Calculate what is leaving tank
+    P = minimum([P, Pmax])
+    ve = sqrt((2 * γ / (γ - 1)) * R * T * (1 - P_amb / P)^((γ - 1) / γ)) |> u"m/s"
+    ρ = P / (R * T) |> u"kg/m^3"
+    ṁ = ρ * a_nozzle * ve |> u"kg/s"
+
+    Thrust = ṁ * ve + a_nozzle * (P - P_amb) |> u"N"
+
+    # Calculate what is still in the tank
+    M = M - ṁ * ts |> u"kg"
+    P = (M * R * T) / V |> u"Pa"
+    t = t + ts
+
+    df_step = DataFrame(Thrust = Thrust, Pressure = P, Time = t, Mass = M)
+    append!(df, df_step)
+end
+println("---------------------------\n\n\n\n")
+println("Total Impulse: ", sum(df.Thrust) * ts)
+println("Burn Time: ", t)
+println("Mass Total: ", Wtank + Wsolenoid + maximum(df.Mass))
+
+print(describe(df))
+plot(df.Time, df.Thrust, title = "Thrust Over Time")
+CSV.write("thrustdata.csv", df .|> ustrip)