Contra-Rotating Propellors: New System Prediction Software

Press Release
Sunday, February 17, 2013

New features for the industry-standard resistance and propulsion software, HydroComp's NavCad.

Many contemporary marine vehicles are being outfitted with contra-rotating propellers (CRP), and naval architects need the ability to model the performance of CRP systems – a capability that has been lacking until now.

As part of its ongoing internal R&D program, HydroComp, Inc. has just deployed a new CRP system analysis module into HydroComp NavCad®, the industry-standard software for the prediction and analysis of vessel speed and power performance.

Published comparisons of the efficiency between standard fixed-pitch propellers (FPP) and CRP propellers typically indicate that CRPs are between 3% and 10% more efficient. It is often presumed that the efficiency gains of a CRP are due solely to recovery of energy lost in the rotational flow of a single propeller.

While recovery of rotational energy is partly responsible for the efficiency gains with a CRP, much of the gain actually occurs due to improved inflow and the reduction in propeller blade loading (with its corresponding change in RPM and blade area ratio).

HydroComp evaluated an extensive catalog of published studies that made direct comparison between FPP and CRP propellers. From the results of this evaluation, a new CRP performance prediction method was developed around a “system-level” model using only the representative definition of one propeller in the set to determine the overall system performance.

The intent of the new CRP method is to reasonably predict the overall performance of a CRP “system”, and is not intended to provide a means to design or size the specific details of the blade sets.

HydroComp’s new CRP (Simple) model includes proper consideration of:

• Thrust and torque division for proper individual blade loading.
• Reduction in loading due accelerated induced velocities.
• Increased efficiency due to improved inflow and recovery of rotational losses 
• Reduced hull efficiency due to rudder interaction. 

 

Maritime Reporter March 2014 Digital Edition
FREE Maritime Reporter Subscription
Latest Maritime News    rss feeds

Technology

RS at SEA JAPAN 2014

Russian Maritime Register of Shipping (RS) was the only Russian company to take part in SEA JAPAN 2014 exhibition and conference – one of the major exhibitions of the maritime industry.

When Will Deep Sea Mining Commence? The Robot is Ready

The world's first deep sea mining robot sits idle on a British factory floor, waiting to claw up high grade copper and gold from the seabed off Papua New Guinea

Havyard to Build Hybrid Battery Arctic PSV

Norway's Havyard says it has signed a contract for the construction of a Havyard 833 WE ICE platform supply vessel with Fafnir Offshore HF. The vessel is to be

Marine Propulsion

RS at SEA JAPAN 2014

Russian Maritime Register of Shipping (RS) was the only Russian company to take part in SEA JAPAN 2014 exhibition and conference – one of the major exhibitions of the maritime industry.

Havyard to Build Hybrid Battery Arctic PSV

Norway's Havyard says it has signed a contract for the construction of a Havyard 833 WE ICE platform supply vessel with Fafnir Offshore HF. The vessel is to be

GE Gas Turbines Power USS America

GE Marine reports that the United States Navy’s future USS America (LHA 6) amphibious assault ship recently completed successful acceptance sea trials powered by two GE LM2500+ marine gas turbines.

Software Solutions

TEPNG Integrates AVEVA Engineering & Design

AVEVA announced that TOTAL E&P Nigeria Ltd. (TEPNG) has adopted AVEVA’s Engineering & Design solutions as part of an Integrated Engineering & Design approach. TEPNG

KVH Precision Sensors for Geodetics' Inertial Navigation Systems

KVH Industries entered into a strategic partnership with Geodetics Inc., a leader in the development of real-time, high-precision position and navigation solutions.

ClassNK Releases EEDI Verification Software – Free

Japanese classification society ClassNK says it offers its Minimum Propulsion Power Calculation Software and ISO-based Progressive Speed Trial Analysis Software

 
 
Maritime Careers / Shipboard Positions Maritime Standards Navigation Pipelines Pod Propulsion Port Authority Salvage Ship Electronics Ship Repair Shipbuilding / Vessel Construction
rss | archive | history | articles | privacy | contributors | top maritime news | about us | copyright | maritime magazines
maritime security news | shipbuilding news | maritime industry | shipping news | maritime reporting | workboats news | ship design | maritime business

Time taken: 0.2989 sec (3 req/sec)