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 August 2015 Digital Edition
FREE Maritime Reporter Subscription
Latest Maritime News    rss feeds

Technology

Hapag-Lloyd Adds 6,000 Reefer Containers

In order to profit from the growing reefer markets in South America and Asia, Hapag-Lloyd has ordered 6,000 cutting-edge reefer containers – more than ever before in the company’s history.

ICTSI Manila Starts Container Booking System

The Manila International Container Terminal (MICT) in the Port of Manila has started implementing a vehicle appointment system called Terminal Appointment Booking

Rosneft, Gazprom to Receive Four Arctic Fields

Ministry of the Environment sent to the government documents on the transfer of "Rosneft" and "Gazprom" licenses for the development of four more fields on the Arctic shelf,

Marine Propulsion

Neander Deal Sees Yanmar Return to Diesel Outboards

Marking its return to the diesel outboard market, engineering company Yanmar Marine International (YMI) has reached an agreement for exclusive distribution rights

Automatic Camera for Monitoring Vessel Engine Developed

NYK and the Monohakobi Technology Institute  have jointly developed “Kirari NINJA” (patent pending), a device that can automatically photograph the interior of a vessel engine’s combustion chamber.

CTruk Delivers Wind Farm Support Vessel

Shipbuilder CTruk Boats, a manufacturer of composite wind farm support vessels (WFSV), has delivered the second workboat in a two-craft order from CWind.   The

Software Solutions

‘Chapplaincy’ for Better Seafarers' Welfare Support

Smartphone App created with support from Augustea Group and MarineTraffic will help charity deliver improved service and better measure impact of its work Sailors’ Society,

Belfast Harbour Goes Live With KleinPort

Saab has commissioned its first Port Management Information System in the UK. As of September 1st, 2015, Belfast Harbour Commission commenced live operations with its KleinPort system.

SHIPFLOW Version 6 Released

SHIPFLOW 6 comes with a new module for computing ship motions in waves and the SHIPFLOW RANS solver is up to 10 times faster than its predecessor.   SHIPFLOW

 
 
Maritime Careers / Shipboard Positions Naval Architecture Navigation Offshore Oil Pipelines Port Authority Ship Repair Shipbuilding / Vessel Construction Sonar Winch
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: 0.3411 sec (3 req/sec)