Submersible Motor Pump Heat-Exchange Passage Design
Solution Overview
Problem
Submersible motor pumps face challenges in effective heat exchange between a coolant and the liquid being pumped, leading to inefficient cooling and potential clogging due to dirt and contaminants, as well as issues with air pockets hindering heat transfer and mechanical seal lubrication and longevity.
Innovation Solution
The design incorporates a centrifugal impeller for circulating coolant, a heat-exchange passage with a large axial component to increase flow velocity and heat transfer area, and an annular wall to separate spaces and expel air, along with a tandem mechanical seal structured as separate assemblies for easier installation and high-pressure operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a water jacket is provided around the motor and a liquid circulates through it to cool the motor, then the motor cooling effect is improved, but the heat exchange efficiency between the coolant and handled liquid is insufficient due to limited space between the motor and pump casing
Solution Approach 1:
The heat exchange passage extends in the axial direction of the centrifugal impeller, utilizing the axial dimension to increase the heat transfer area. This resolves the space limitation by expanding the heat exchange surface area along the axial direction rather than being constrained only by the radial space between motor and pump casing.
2Productivity
If a tandem mechanical seal with a centrifugal impeller is used to circulate coolant, then the coolant circulation capability is improved, but the structure becomes complex and assembly becomes difficult
Solution Approach 1:
The centrifugal impeller is integrated directly onto the rotational shaft of the tandem mechanical seal, merging the coolant circulation function with the existing seal structure. This eliminates the need for a separate circulation mechanism and simplifies the overall structure while maintaining effective coolant circulation capability.
3Device complexity
If air pockets are present in the housing space of the main impeller, then the structure is simple, but heat exchange between coolant and handled liquid is hindered and mechanical seal lubrication is compromised
Solution Approach 1:
The air pocket is actively expelled from the housing space of the main impeller through the heat exchange passage design, removing the harmful air pocket that hinders heat exchange and lubrication. This ensures continuous liquid contact for effective heat transfer and proper mechanical seal lubrication.
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
This configuration enhances heat exchange efficiency, prevents clogging, and extends mechanical seal life by ensuring effective coolant circulation and air expulsion, improving overall pump performance.
Implementation Method 1
a centrifugal impeller, which pressurizes the coolant
Implementation Method 2
the cooling action by the coolant is based on forced convection heat transfer
Implementation Method 3
heat exchange between the coolant and the handled liquid through a heat-exchange passage
Implementation Method 4
a tandem mechanical seal, which has two mechanical seals arranged in series, is conventionally used as a seal mechanism for separating the motor from the handled liquid
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A submersible motor pump includes a water jacket (11) having a circulation passage (24A, 24B, 24C, and 24D) of a coolant, a centrifugal impeller (20) for circulating the coolant, a suction passage configured to provide fluid communication between the circulation passage (24A, 24B, 24C, and 24D) and a fluid inlet of the centrifugal impeller (20), and a discharge passage configured to provide fluid communication between a fluid outlet of the centrifugal impeller (20) and the circulation passage (24A, 24B, 24C, and 24D). The discharge passage includes a heat-exchange passage (80) formed by two wall surfaces, one of which is constituted by a member which contacts a liquid conveyed by a main impeller (12). The heat-exchange passage (80) has a circular shape extending radially outwardly from the fluid outlet of the centrifugal impeller (20). The heat-exchange passage (80) includes at least one axial passage section having a length component in an axial direction of the rotational shaft (1).