Embedded-Motor Turbomachine Layout for Compact Wet Gas Compression

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Solution Overview

Problem

Current turbomachines designed for processing mixed gas/liquid flows, particularly wet gas with a gas volume fraction greater than 80%, face efficiency drops when operating far from design conditions, and are limited by axial length and power constraints, leading to complexity and reduced pressure rise capabilities.

Innovation Solution

A multistage turbomachine design with counter-rotating impellers arranged directly adjacent to each other without stationary blades, and independently controlled electric motors to optimize rotational speeds based on gas volume fraction, allowing for reduced axial length and improved efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multistage pumps and compressors with co-axial shafts and counter-rotating impellers are used, then the ability to handle mixed gas/liquid flows is improved, but the device complexity increases

Engineering Contradiction:
Improveability to handle mixed gas/liquid flowsVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the drive mechanisms of counter-rotating impellers into a single electric motor with two rotors sharing a common stator, eliminating the need for two separate co-axial shafts and their associated bearings. This integration reduces mechanical complexity while maintaining the ability to handle mixed gas/liquid flows through counter-rotating impellers.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single electric motor with dual rotors performs the function of two separate motors, providing both counter-rotating impeller drive capabilities in one integrated unit. This multi-functional design reduces the number of components while maintaining versatility in handling mixed phase flows.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Length of moving object

If the axial length of the turbomachine is reduced, then the power available is limited, but the device length constraint is satisfied

Engineering Contradiction:
Improveaxial lengthVSAvoidpower available
Core Design Contradiction:
Length of moving objectVSPower

Solution Approach 1:

The patent transitions from a traditional axial arrangement where power is limited by length to a radial arrangement where the motor stator surrounds the rotors. This dimensional change allows the magnetic field to generate torque radially, enabling high power density in a compact axial footprint while satisfying subsea length constraints.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent nests one rotor inside another rotor, with both rotors sharing a common stator. This nested configuration maximizes the use of available space, allowing both impellers to be driven within a compact axial envelope while maintaining sufficient power capacity for mixed phase flow handling.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Length of moving object

If high rotary speed is used to reduce motor length, then the life of the turbomachine is reduced

Engineering Contradiction:
Improvemotor lengthVSAvoidlife of the turbomachine
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The patent employs dynamic control of the dual rotors, allowing independent speed and torque adjustment of each impeller. This dynamic capability enables operation at optimized speeds that balance motor compactness with reduced mechanical stress, extending turbomachine life while maintaining acceptable length through intelligent speed management rather than simply increasing rotational speed.

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The design enhances efficiency and reduces axial length, enabling better handling of mixed gas/liquid flows by optimizing impeller speeds and motor control, thus alleviating the limitations of existing turbomachines.

Implementation Method 1

Each stage is driven into rotation by a respective embedded electric motor

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 2

The turbomachine comprises a plurality of stages, arranged in sequence from an inlet towards an outlet, each stage comprising a rotating impeller

Methodology Applied
Scientific EffectImpeller-driven fluid motion: Impeller

Data Source

PatentEP3102833B1Multistage turbomachine with embedded electric motors
Publication Date: 2021.03.31 NUOVO PIGNONE SPA
  • EP3102833B1 patent drawingFigure 1
  • EP3102833B1 patent drawingFigure 2
  • EP3102833B1 patent drawingFigure 3

AI summary

A multistage turbomachine (1) is disclosed, comprising a casing (3) with a fluid inlet (5) and a fluid outlet (7), and a plurality of stages (13A, 13B) arranged in the casing (3). A flow path extends from the fluid inlet (5) to the fluid outlet (7) through the sequentially arranged stages (13A, 13B). Each stage is comprised of a rotating impeller (17A, 17B) and an electric motor embedded in the casing (3) and arranged for rotating the impeller (17A, 17B) at a controlled rotary speed. Each electric motor comprises a motor rotor (31A, 31B), arranged on the impeller (17A, 17B) and integrally rotating therewith, and a motor stator (33A, 33B) stationarily arranged in the casing (3). Pairs of sequentially arranged impellers are configured for rotation in opposite directions.