04waterjet - Waterjet first draft 9/23/04 from Prof....

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Waterjet first draft 9/23/04 from Prof. Carmichael notes. 9/17/06: modified to reflect w (V=>V A ) and separate inlet and outlet pressure loss (in addition to drag) to reflect paper V A velocity inlet w wake fraction Vs ship velocity Vj nozzle (outlet) velocity V A := V s (1 w) T = m_dot ( V J V A ) m_dot = mass_flow_rate d h Vj V A ρ g d at inlet centerline . .. p local = p atmos + at this point . .. total pressure (pitot tube) p oin = p local + 1 ⋅ρ⋅ V A 2 = p atmos + ρ⋅ g d + 1 ⋅ρ⋅ V A 2 2 2 pressure at inlet to pump . .. 1 2 total pressure (pitot tube) . .. p op = p oin ρ⋅ g (d + h) = p atmos ρ⋅ g h + 2 ⋅ρ⋅ V A pressure at pump exit. .. total p oj = p atmos + 1 2 ⋅ρ⋅ V j 2 pressure (pitot tube) . . total pressure increase across pump . .. p oj p op = p atmos + 2 1 ⋅ρ⋅ V j 2 p atmos + ρ⋅ g h 2 1 ⋅ρ⋅ V A 2 = 2 1 ⋅ρ⋅ V j 2 V A 2 + ρ⋅ g h energy rise across the pump p oj p op 1 2 2 per unit mass flow is . .. ρ = 2 V j V A + gh power absorbed by ideal pump is p oj p op 1 2 2 therefore . .. P pi = m_dot ρ = m_dot 2 V j V A + gh ideal efficiency is then . .. and quasi propulsive coefficient is . .. ) T P Ti effective_power P E RV s (1 t V s 1 t TV A 1 t P Ti 1 t η i = η D = = = = = = = ⋅η i P pi power_delivered P pi P Pi P Pi 1 w P Pi 1 w P pi 1 w V J P Ti TV A m_dot V A V J ) 2V A V J ) 2V
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 4

04waterjet - Waterjet first draft 9/23/04 from Prof....

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online