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Special Issue "Thermal Switches and Control of Heat Transfer in MEMS"

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A special issue of Micromachines (ISSN 2072-666X).

Deadline for manuscript submissions: closed (15 March 2012)

Special Issue Editors

Guest Editor
Prof. Dr. Robert F. Richards (Website)

School of Mechanical and Materials Engineering, Washington State University, PO Box 642920, Pullman, WA 99164-2920, USA
Fax: +1 509 335 4662
Interests: MEMS; actuators; sensors; energy conversion; micropower; heat and mass transfer
Guest Editor
Prof. Dr. Cecilia D. Richards (Website)

School of Mechanical and Materials Engineering, Washington State University PO BOX 642920, Pullman, WA 99164-2920, USA
Phone: 509 335 7753
Interests: MEMS power; Advanced energy systems; Two-phase flows; thermal processes in MEMS

Special Issue Information

Dear Colleagues,

The control of heat transfer rates in microdevices is a crucial issue, driven by numerous important applications in micropower, microcooling and lab-on-a-chip. Applications include stable temperature control of frequency standards such as a chip-scale atomic clocks, rapid cycling between different temperatures as in DNA amplification via Polymerase Chain Reaction (PCR), or controlling intermittent heat transfer to boost the efficiency of thermoelectric microcoolers working in pulsed operation. MEMS-based thermal switches offer a promising approach to meet these needs. In view of recent advances in this rapidly developing new field, it seems beneficial to publish a volume in Micromachines dedicated to thermal switching and MEMS thermal control. Accordingly, we hereby announce a special issue addressing advances in design, modeling, fabrication, characterization and novel applications of micromachined thermal switches. We invite submission of papers on devices for control of heat transfer on small time and length scales, including principles of microscale thermal control, and new architectures for thermal switching. Related novel systems concepts, new applications for thermal switching, and methods of device measurement/characterization are of interest.

We look forward to receiving your valuable contributions!

Dr. Robert F. Richards
Dr. Cecilia D. Richards
Guest Editors

Submission

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. Papers will be published continuously (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are refereed through a peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Micromachines is an international peer-reviewed Open Access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1000 CHF (Swiss Francs).

Keywords

  • thermal switch
  • thermal valve
  • temperature control
  • temperature cycling
  • pulsed heat addition/rejection
  • pulsed thermoelectric
  • magnetic refrigeration
  • micro heat engine
  • spacecraft thermal control
  • thermal isolation
  • thermal contact
  • MEMS
  • micromachining
  • thermal actuation

Published Papers (4 papers)

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Research

Open AccessArticle Characterization of Kink Actuators as Compared to Traditional Chevron Shaped Bent-Beam Electrothermal Actuators
Micromachines 2012, 3(3), 542-549; doi:10.3390/mi3030542
Received: 10 May 2012 / Revised: 19 June 2012 / Accepted: 3 July 2012 / Published: 6 July 2012
Cited by 4 | PDF Full-text (1963 KB) | HTML Full-text | XML Full-text
Abstract
This paper compares the design and performance of kink actuators, a modified version of the bent-beam thermal actuator, to the standard chevron-shaped designs. A variety of kink and chevron actuator designs were fabricated from polysilicon. While the actuators were electrically probed, these [...] Read more.
This paper compares the design and performance of kink actuators, a modified version of the bent-beam thermal actuator, to the standard chevron-shaped designs. A variety of kink and chevron actuator designs were fabricated from polysilicon. While the actuators were electrically probed, these designs were tested using a probe station connected to a National Instruments (NI) controller that uses LabVIEW to extract the displacement results via image processing. The displacement results were then used to validate the thermal-electric-structural simulations produced by COMSOL. These results, in turn, were used to extract the stiffness for both actuator types. The data extracted show that chevron actuators can have larger stiffness values with increasing offsets, but at the cost of lower amplification factors. In contrast, kink actuators showed a constant stiffness value equivalent to the chevron actuator with the highest amplification factor. The kink actuator also had larger amplification factors than chevrons at all designs tested. Therefore, kink actuators are capable of longer throws at lower power levels than the standard chevron designs. Full article
(This article belongs to the Special Issue Thermal Switches and Control of Heat Transfer in MEMS)
Figures

Open AccessArticle MEMS-Based Boiler Operation from Low Temperature Heat Transfer and Thermal Scavenging
Micromachines 2012, 3(2), 331-344; doi:10.3390/mi3020331
Received: 16 March 2012 / Revised: 31 March 2012 / Accepted: 18 April 2012 / Published: 26 April 2012
Cited by 7 | PDF Full-text (1332 KB) | HTML Full-text | XML Full-text
Abstract
Increasing world-wide energy use and growing population growth presents a critical need for enhanced energy efficiency and sustainability. One method to address this issue is via waste heat scavenging. In this approach, thermal energy that is normally expelled to the environment is [...] Read more.
Increasing world-wide energy use and growing population growth presents a critical need for enhanced energy efficiency and sustainability. One method to address this issue is via waste heat scavenging. In this approach, thermal energy that is normally expelled to the environment is transferred to a secondary device to produce useful power output. This paper investigates a novel MEMS-based boiler designed to operate as part of a small-scale energy scavenging system. For the first time, fabrication and operation of the boiler is presented. Boiler operation is based on capillary action that drives working fluid from surrounding reservoirs across a heated surface. Pressure is generated as working fluid transitions from liquid to vapor in an integrated steamdome. In a full system application, the steam can be made available to other MEMS-based devices to drive final power output. Capillary channels are formed from silicon substrates with 100 µm widths. Varying depths are studied that range from 57 to 170 µm. Operation of the boiler shows increasing flow-rates with increasing capillary channel depths. Maximum fluid mass transfer rates are 12.26 mg/s from 170 µm channels, an increase of 28% over 57 µm channel devices. Maximum pressures achieved during operation are 229 Pa. Full article
(This article belongs to the Special Issue Thermal Switches and Control of Heat Transfer in MEMS)
Figures

Open AccessArticle Mechanical Vibrations of Thermally Actuated Silicon Membranes
Micromachines 2012, 3(2), 255-269; doi:10.3390/mi3020255
Received: 14 February 2012 / Revised: 14 March 2012 / Accepted: 26 March 2012 / Published: 28 March 2012
Cited by 1 | PDF Full-text (2243 KB) | HTML Full-text | XML Full-text
Abstract
A thermally-actuated micro-electro-mechanical (MEMS) device based on a vibrating silicon membrane has been proposed as a viscosity sensor by the authors. In this paper we analyze the vibration mode of the sensor as it vibrates freely at its natural frequency. Analytical examination [...] Read more.
A thermally-actuated micro-electro-mechanical (MEMS) device based on a vibrating silicon membrane has been proposed as a viscosity sensor by the authors. In this paper we analyze the vibration mode of the sensor as it vibrates freely at its natural frequency. Analytical examination is compared to finite element analysis, electrical measurements and the results obtained through real-time dynamic optical surface profilometry. The vertical movement of the membrane due to the applied heat is characterized statically and dynamically. The natural vibration mode is determined to be the (1,1) mode and good correlation is found between the analytical predictions, the simulation analysis, the observed mechanical displacement and the electrical measurements. Full article
(This article belongs to the Special Issue Thermal Switches and Control of Heat Transfer in MEMS)
Open AccessArticle Switchable Thermal Interfaces Based on Discrete Liquid Droplets
Micromachines 2012, 3(1), 10-20; doi:10.3390/mi3010010
Received: 5 December 2011 / Revised: 22 December 2011 / Accepted: 22 December 2011 / Published: 6 January 2012
Cited by 7 | PDF Full-text (779 KB) | HTML Full-text | XML Full-text
Abstract
We present a switchable thermal interface based on an array of discrete liquid droplets initially confined on hydrophilic islands on a substrate. The droplets undergo reversible morphological transition into a continuous liquid film when they are mechanically compressed by an opposing substrate [...] Read more.
We present a switchable thermal interface based on an array of discrete liquid droplets initially confined on hydrophilic islands on a substrate. The droplets undergo reversible morphological transition into a continuous liquid film when they are mechanically compressed by an opposing substrate to create low-thermal resistance heat conduction path. We investigate a criterion for reversible switching in terms of hydrophilic pattern size and liquid volume. The dependence of the liquid morphology and rupture distance on the diameter and areal fraction of hydrophilic islands, liquid volumes, as well as loading pressure is also characterized both theoretically and experimentally. The thermal resistance in the on-state is experimentally characterized for ionic liquids, which are promising for practical applications due to their negligible vapor pressure. A life testing setup is constructed to evaluate the reliability of the interface under continued switching conditions at relatively high switching frequencies. Full article
(This article belongs to the Special Issue Thermal Switches and Control of Heat Transfer in MEMS)

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