Overall hydraulic performance prediction method for sink-type dishwasher
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Solution Overview
Problem
Existing simulation technologies face challenges in accurately simulating the internal turbulence mechanism of sink-type dishwashers due to complex multi-physics problems, including turbulence model selection, excessive resource consumption, and difficulties in achieving convergence and mass conservation caused by the passive rotation of the volute and free surface flow.
Innovation Solution
A step-by-step multi-physics coupling simulation method is employed, involving numerical simulations of the composite impeller and twin-volute spraying arm, using methods like GMO-TruVOF and FAVOR-TruVOF to simulate the passive rotation of the volute and non-submerged jet flow, with a virtual impeller model to simplify the simulation and reduce computational burden.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct simulation of the internal turbulence mechanism is performed, then the flow field can be described, but the computation is difficult to converge and requires complex turbulence models
Solution Approach 1:
The simulation is divided into two separate stages: first simulating the pump body flow field to obtain outlet flow distribution, then using this distribution as boundary conditions for the spray arm simulation. This segmentation avoids the convergence issues of direct full-system simulation while maintaining flow field description accuracy.
Solution Approach 2:
The pump body simulation is performed first to preliminarily determine the flow distribution at the spray arm inlet. This preliminary action provides accurate boundary conditions for the subsequent spray arm simulation, eliminating the need for complex coupled turbulence modeling.
2Measurement precision
If passive rotation of the volute is simulated, then the rotating jet flow can be captured, but the dynamic mesh varies in negative angle and mass conservation is lost
Solution Approach 1:
The volute rotation is simulated dynamically by applying rotational velocity boundary conditions rather than using dynamic mesh. This approach captures the rotating jet flow characteristics while avoiding the numerical instability and mass conservation issues associated with dynamic mesh methods.
3Measurement precision
If comprehensive simulation of all components is performed, then overall hydraulic performance can be predicted, but excessive computing resources are consumed
Solution Approach 1:
The hydraulic performance prediction is segmented into two independent simulation stages with distinct boundary conditions. This allows each stage to be optimized separately and avoids the excessive computational resources required for fully coupled simulation, while still providing comprehensive hydraulic performance prediction.
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 approach significantly reduces computational resources while enhancing the accuracy and fidelity of hydraulic performance prediction, addressing issues of dynamic mesh variability and mass conservation, and providing a comprehensive simulation of the dishwasher's flow characteristics.
Implementation Method 1
The passive rotation involves the problems of gas-liquid two-phase flow, free surface flow, six-degree-of-freedom motion, and fluid-structure interaction
Implementation Method 2
The passive rotation involves the problems of gas-liquid two-phase flow, free surface flow, six-degree-of-freedom motion, and fluid-structure interaction
Implementation Method 3
The rotating jet flow is subject to the category of non-submerged jet flow, and also involves the problems of free surface flow and gas-liquid two-phase flow
Data Source
AI summary
Method for predicting the overall hydraulic performance of a sink-type dishwasher. Process begins with unsteady numerical computation on a dishwasher pump under static conditions to obtain a characteristic pump curve. Using this curve, rotation velocity adaptation coefficient (Ad) and axial velocity coefficient (Bd) are determined. Mapping relationship is established between composite superposition virtual impeller and composite impeller. Passive rotation velocity of the volute and the nozzle flow rate are calculated using GMO model and virtual impeller. A jet mass source is established, using the nozzle flow rate and the volute's passive rotation velocity as boundary conditions. This leads to a non-submerged rotating jet flow computation with a multi-nozzle setup using the VOF method. This approach streamlines the dishwasher's intricate multi-physics, conserves computing resources, and effectively resolves issues related to free surface divergence and estimating the volute's passive rotation speed, leading to an accurate prediction of the dishwasher's overall hydraulic performance.