Design Optimization of Fixed-Valve Micropumps for Miniature Cooling Systems

2007 ◽  
Author(s):  
Fred K. Forster ◽  
Travis Walter
Keyword(s):  
Fluid Dynamic ◽  
Low Cost ◽  
System Modeling ◽  
Load Flow ◽  
Extended Model ◽  
Liquid Cooling ◽  
Cooling Systems ◽  
Load Pressure ◽  
Pump Design ◽  
Pump Performance

The piezoelectrically driven fixed-valve micropump may be an attractive choice for miniature liquid cooling systems due to its low-cost potential and simple fabrication. The thin, stackable design can be fabricated in many materials, including silicon, metal and plastic. Previous linear system modeling has been used to predict resonant behavior in terms of valve Reynolds number and used as a guideline for design, but can not yield predictions of pressure and flow, which depend on nonlinear fluid dynamic phenomena. In this study we report an extended model that incorporates the calculation of block-load pressure and no-load flow in a manner such that thousands of designs can be analyzed quickly. The results indicate that by calculating these two pump performance parameters over a design space of valve size and actuator stiffness, pump design is better able to match pump performance to system requirements. Experimental verification was performed using prototype pumps with interchangeable plastic and metal parts to demonstrate the approach for these two low cost materials.

The Effect of Air Injection Method on the Airlift Pump Performance

2012 ◽  
Vol 134 (11) ◽  
Author(s):  
Dong Hu ◽  
Chuan-Lin Tang ◽  
Shu-Peng Cai ◽  
Feng-Hua Zhang
Keyword(s):  
Flow Rate ◽  
Volume Flow Rate ◽  
Low Cost ◽  
Air Injection ◽  
Water Volume ◽  
Pump Design ◽  
Pump Performance ◽  
Dimensionless Equation ◽  
Measurement Results ◽  
Injection Methods

With simple structure, excellent reliability, low cost, no restriction at depth of water, and easy control and operation, airlift pumps have special advantage in borehole hydraulic jet mining, river dredging and deep sea mining. To clarify the mechanism and process of action of air injection methods on air lift performance, and to enhance lifting capacity, the pump performance of a small airlift system in transporting river sands is investigated experimentally in the present study. The results are as the follows. The influences of air exit ports on water volume flow rate, mass flow rate of solids and lifting efficiency are studied and found to be very low when the number of air exit ports exceeds 3. The pump design show best pumping capability for water and solids at higher air flow rates, but the lifting efficiency is then very low. In addition, a dimensionless equation which describes the flows in the pipe is presented based on the Bernoulli equation, and compared with measurement results in the dimensionless form, which are nearly in good agreement with each other for all the arrangements of air exit ports and are basically contained within ±18% of the theoretical curve. The results are important for understanding the mechanism of airlift pumps and enriching multiphase flow theory.

Improvements in Fixed-Valve Micropump Performance Through Shape Optimization of Valves

2004 ◽  
Vol 127 (2) ◽  
pp. 339-346 ◽  
Author(s):  
Adrian R. Gamboa ◽  
Christopher J. Morris ◽  
Fred K. Forster
Keyword(s):  
Shape Optimization ◽  
Dynamic Model ◽  
Flow Resistance ◽  
Load Flow ◽  
Maximum Output ◽  
Load Pressure ◽  
Pump Design ◽  
Number Range ◽  
Forward Flow ◽  
Linear Dynamic

The fixed-geometry valve micropump is a seemingly simple device in which the interaction between mechanical, electrical, and fluidic components produces a maximum output near resonance. This type of pump offers advantages such as scalability, durability, and ease of fabrication in a variety of materials. Our past work focused on the development of a linear dynamic model for pump design based on maximizing resonance, while little has been done to improve valve shape. Here we present a method for optimizing valve shape using two-dimensional computational fluid dynamics in conjunction with an optimization procedure. A Tesla-type valve was optimized using a set of six independent, non-dimensional geometric design variables. The result was a 25% higher ratio of reverse to forward flow resistance (diodicity) averaged over the Reynolds number range 0<Re⩽2000 compared to calculated values for an empirically designed, commonly used Tesla-type valve shape. The optimized shape was realized with no increase in forward flow resistance. A linear dynamic model, modified to include a number of effects that limit pump performance such as cavitation, was used to design pumps based on the new valve. Prototype plastic pumps were fabricated and tested. Steady-flow tests verified the predicted improvement in diodicity. More importantly, the modest increase in diodicity resulted in measured block-load pressure and no-load flow three times higher compared to an identical pump with non-optimized valves. The large performance increase observed demonstrated the importance of valve shape optimization in the overall design process for fixed-valve micropumps.

scholarly journals Investigation on Thermal Resistance and Capacitance Characteristics of a Highly Integrated Power Control Unit Module

Electronics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 958
Author(s):  
Maosheng Zhang ◽  
Yu Bai ◽  
Shu Yang ◽  
Kuang Sheng
Keyword(s):  
Thermal Resistance ◽  
Power Control ◽  
Electric Vehicles ◽  
Low Cost ◽  
Control Unit ◽  
Underlying Mechanism ◽  
Power Converter ◽  
Liquid Cooling ◽  
Integration Density ◽  
Unit Module

With the increasing integration density of power control unit (PCU) modules, more functional power converter units are integrated into a single module for applications in electric vehicles or hybrid electric vehicles (EVs/HEVs). Different types of power dies with different footprints are usually placed closely together. Due to the constraints from the placement of power dies and liquid cooling schemes, heat-flow paths from the junction to coolant are possibly inconsistent for power dies, resulting in different thermal resistance and capacitance (RC) characteristics of power dies. This presents a critical challenge for optimal liquid cooling at a low cost. In this paper, a highly integrated PCU module is developed for application in EVs/HEVs. The underlying mechanism of the inconsistent RC characteristics of power dies for the developed PCU module is revealed by experiments and simulations. It is found that the matching placement design of power dies with a heat sink structure and liquid cooler, as well as a liquid cooling scheme, can alleviate the inconsistent RC characteristics of power dies in highly integrated PCU modules. The findings in this paper provide valuable guidance for the design of highly integrated PCU modules.

scholarly journals Experiments on Energy-Efficient Evaporative Cooling Systems for Poultry Farm Application in Multan (Pakistan)

2021 ◽  
Vol 13 (5) ◽  
pp. 2836
Author(s):  
Khawar Shahzad ◽  
Muhammad Sultan ◽  
Muhammad Bilal ◽  
Hadeed Ashraf ◽  
Muhammad Farooq ◽  
...  
Keyword(s):  
Heat Stress ◽  
Low Cost ◽  
Evaporative Cooling ◽  
Thermal Exposure ◽  
Climatic Conditions ◽  
The Body ◽  
Dew Point ◽  
Sweat Glands ◽  
Cooling Systems ◽  
Humidity Index

Poultry are one of the most vulnerable species of its kind once the temperature-humidity nexus is explored. This is so because the broilers lack sweat glands as compared to humans and undergo panting process to mitigate their latent heat (moisture produced in the body) in the air. As a result, moisture production inside poultry house needs to be maintained to avoid any serious health and welfare complications. Several strategies such as compressor-based air-conditioning systems have been implemented worldwide to attenuate the heat stress in poultry, but these are not economical. Therefore, this study focuses on the development of low-cost and environmentally friendly improved evaporative cooling systems (DEC, IEC, MEC) from the viewpoint of heat stress in poultry houses. Thermodynamic analysis of these systems was carried out for the climatic conditions of Multan, Pakistan. The results appreciably controlled the environmental conditions which showed that for the months of April, May, and June, the decrease in temperature by direct evaporative cooling (DEC), indirect evaporative cooling (IEC), and Maisotsenko-Cycle evaporative cooling (MEC) systems is 7–10 °C, 5–6.5 °C, and 9.5–12 °C, respectively. In case of July, August, and September, the decrease in temperature by DEC, IEC, and MEC systems is 5.5–7 °C, 3.5–4.5 °C, and 7–7.5 °C, respectively. In addition, drop in temperature-humidity index (THI) values by DEC, IEC, and MEC is 3.5–9 °C, 3–7 °C, and 5.5–10 °C, respectively for all months. Optimum temperature and relative humidity conditions are determined for poultry birds and thereby, systems’ performance is thermodynamically evaluated for poultry farms from the viewpoint of THI, temperature-humidity-velocity index (THVI), and thermal exposure time (ET). From the analysis, it is concluded that MEC system performed relatively better than others due to its ability of dew-point cooling and achieved THI threshold limit with reasonable temperature and humidity indexes.

Computational Fluid Dynamic Applications for Jet Propulsion System Integration

1991 ◽  
Vol 113 (1) ◽  
pp. 40-50 ◽  
Author(s):  
R. H. Tindell
Keyword(s):  
System Integration ◽  
Fluid Dynamic ◽  
Low Cost ◽  
Separated Flow ◽  
Propulsion System ◽  
Navier Stokes ◽  
Aerospace Vehicles ◽  
Design Engineers ◽  
Flow Phenomena ◽  
The Impact

The impact of computational fluid dynamics (CFD) methods on the development of advanced aerospace vehicles is growing stronger year by year. Design engineers are now becoming familiar with CFD tools and are developing productive methods and techniques for their applications. This paper presents and discusses applications of CFD methods used at Grumman to design and predict the performance of propulsion system elements such as inlets and nozzles. The paper demonstrates techniques for applying various CFD codes and shows several interesting and unique results. A novel application of a supersonic Euler analysis of an inlet approach flow field, to clarify a wind tunnel-to-flight data conflict, is presented. In another example, calculations and measurements of low-speed inlet performance at angle of attack are compared. This is highlighted by employing a simplistic and low-cost computational model. More complex inlet flow phenomena at high angles of attack, calculated using an approach that combines a panel method with a Navier-Stokes (N-S) code, is also reviewed. The inlet fluid mechanics picture is rounded out by describing an N-S calculation and a comparison with test data of an offset diffuser having massively separated flow on one wall. Finally, the propulsion integration picture is completed by a discussion of the results of nozzle-afterbody calculations, using both a complete aircraft simulation in a N-S code, and a more economical calculation using an equivalent body of revolution technique.

scholarly journals Enhancing Radiation Detection by Drones through Numerical Fluid Dynamics Simulations

Sensors ◽  
2020 ◽  
Vol 20 (6) ◽  
pp. 1770 ◽  
Author(s):  
Fabio Marturano ◽  
Jean-François Ciparisse ◽  
Andrea Chierici ◽  
Francesco d’Errico ◽  
Daniele Di Giovanni ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Nuclear Power ◽  
Situational Awareness ◽  
Fluid Dynamic ◽  
Low Cost ◽  
Radiation Detection ◽  
First Responders ◽  
Decision Makers ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations

This study addresses the optimization of the location of a radioactive-particle sensor on a drone. Based on the analysis of the physical process and of the boundary conditions introduced in the model, computational fluid dynamics simulations were performed to analyze how the turbulence caused by drone propellers may influence the response of the sensors. Our initial focus was the detection of a small amount of radioactivity, such as that associated with a release of medical waste. Drones equipped with selective low-cost sensors could be quickly sent to dangerous areas that first responders might not have access to and be able to assess the level of danger in a few seconds, providing details about the source terms to Radiological-Nuclear (RN) advisors and decision-makers. Our ultimate application is the simulation of complex scenarios where fluid-dynamic instabilities are combined with elevated levels of radioactivity, as was the case during the Chernobyl and Fukushima nuclear power plant accidents. In similar circumstances, accurate mapping of the radioactive plume would provide invaluable input-data for the mathematical models that can predict the dispersion of radioactivity in time and space. This information could be used as input for predictive models and decision support systems (DSS) to get a full situational awareness. In particular, these models may be used either to guide the safe intervention of first responders or the later need to evacuate affected regions.

scholarly journals A novel design for sampling benthic zooplankton communities in disparate Gulf of Alaska habitats using an autonomous deep-water plankton pump

2020 ◽  
Vol 42 (4) ◽  
pp. 457-466
Author(s):  
Rachel E Wilborn ◽  
Christopher N Rooper ◽  
Pam Goddard ◽  
Kresimir Williams ◽  
Rick Towler
Keyword(s):  
Deep Water ◽  
Cold Water ◽  
Larval Fish ◽  
Low Cost ◽  
Benthic Communities ◽  
Gulf Of Alaska ◽  
Design Parameters ◽  
Benthic Habitat ◽  
Pump Design ◽  
Zooplankton Communities

Abstract Deep-water larval fish and zooplankton utilize structurally complex, cold-water coral and sponge (CWCS) habitats as refuges, nurseries and feeding grounds. Fine-scale sampling of these habitats for larval fish and zooplankton has proven difficult. This study implemented a newly designed, autonomous, noninvasive plankton pump sampler that collected large mesozooplankton within 1 m of the seafloor. It was successfully deployed in the western Gulf of Alaska between the Shumagin Islands (~158°W) and Samalga Pass (−170°W), and collected in situ zooplankton from diverse benthic communities (coral, sponge and bare substrates) at depths in excess of 100 m. Key design parameters of the plankton pump were its ability to be deployed from ships of opportunity, be untethered from the vessel during sampling and be deployed and retrieved in high-relief, rocky areas where CWCS are typically present. The plankton pump remains stationary while collecting from the water column, rests within 1 m of the seafloor and captures images of the surrounding habitat and substrate. This plankton pump design is a low-cost, highly portable solution for assessing the role of benthic habitat in the life cycle of mesozooplankton, a linkage that has been relatively underexplored due to the difficulty in obtaining near-bottom samples.

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