Electric pump-fed cycle — modern innovation

3.3.26 · Physics › Rocket Propulsion

PUMP exist kyun karta hai bilkul bhi?

Feed cycles ki teen families

Pump power ko first principles se derive karna

KAISE — derive karo:

Liquid ke chhote volume $dV$ ko pressure $\Delta p$ se upar dhakeline ka kaam: $dW=\Delta pdV$

Time $dt$ se divide karo. Volume flow rate hai $\dot{V}=dV/dt$: $P_{\text{ideal}}=\Delta p\dot{V}$

Ab $\dot{V}$ ko mass flow rate $\dot{m}$ aur density $\rho$ se express karo, kyunki $\dot{m}=\rho \dot{V}\Rightarrow \dot{V}=\dot{m}/\rho$:

Aur motor battery se draw karta hai, motor+controller efficiency ${\eta }_m$ ke saath: $P_{\text{elec}}=\frac{P_{\text{shaft}}}{{\eta }_m}=\frac{\dot{m}\Delta p}{\rho {\eta }_p{\eta }_m}$

Kitna battery mass? (sabse bada trade-off)

Burn time $t_b$ mein energy: $E=P_{\text{elec}}{t}_b=\frac{\dot{m}\Delta p}{\rho {\eta }_p{\eta }_m}{t}_b$

Aap aksar spent batteries ko burn ke beech mein drop kar sakte ho (jaise Rocket Lab ka Rutherford karta hai) toh dead battery mass ko burnout tak carry nahi karna padta.

Worked examples

Common mistakes

Active recall

Flashcards

Connections

• Rocket Propulsion
• Turbopump-fed cycle (gas generator vs staged combustion)
• Pressure-fed cycle
• Specific impulse (Isp)
• Tsiolkovsky rocket equation — battery mass mass ratio $m_0/m_f$ ko hurt karta hai
• Bernoulli's principle — pressure = energy per unit volume
• Battery specific energy
• Rocket Lab Rutherford engine

Concept Map