Tesla valve

The valves are structures that have a higher pressure drop for the flow in one direction (reverse) than the other (forward). This difference in flow resistance causes a net directional flow rate in the forward direction in oscillating flows. The efficiency is often expressed in diodicity $\backslash mathrm\{Di\}$, being the ratio of directional resistances.

The flow resistance is defined, analogously to Ohm's law for electrical resistance, as the ratio of applied pressure drop and resulting flow rate:

$R\; =\; \backslash frac\{\backslash Delta\; p\}\{Q\}$ where $\backslash Delta\; p$ is the applied pressure difference between two ends of the conduit, and $Q$ the flow rate.

The diodicity is then the ratio of the reversed flow resistance to the forward flow resistance:

$\backslash mathrm\; \{Di\}\; =\; \backslash frac\{R\_\{\backslash rm\; r\}\}\{R\_\{\backslash rm\; f\}\}$. If $\backslash mathrm\; \{Di\}\; >1$, the conduit in question has diodic behavior.

Thus diodicity is also the ratio of pressure drops for identical flow rates:

$$\backslash mathrm\; \{Di\}\; =\; \backslash left(\; \backslash frac\{\backslash Delta\; p\_\{\backslash rm\; r\}\}\{\backslash Delta\; p\_\{\backslash rm\; f\}\}\; \backslash right)\_Q,$$

where $\backslash Delta\; p\_\{\backslash rm\; r\}$ is the reverse flow pressure drop, and $\backslash Delta\; p\_\{\backslash rm\; f\}$ the forward flow pressure drop for flow rate $Q$.

Equivalently, diodicity could also be defined as ratio of dimensionless Hagen number or Darcy friction factor at the same Reynolds number.

With no moving parts, Tesla valves are much more resistant to wear and fatigue, especially in applications with frequent pressure reversal such as a pulsejet.{{Cite journal |url=http://link.springer.com/article/10.1007/s12213-013-0069-1 |title=Numerical study on the performance of Tesla type microvalve in a valveless micropump in the range of low frequencies |last1=Mohammadzadeh|first1=K. |last2=Kolahdouz|first2=Ebrahim M. |last3=Shirani|first3=E. |last4=Shafii |first4=M. B. |journal=Journal of Micro-Bio Robotics |year=2013 |volume=8 |issue=3–4 |pages=145–159 |url-access=subscription |doi=10.1007/s12213-013-0069-1 |s2cid=109638783 |access-date=2021-05-12 |archive-date=2021-04-23 |archive-url=https://web.archive.org/web/20210423211730/https://link.springer.com/article/10.1007/s12213-013-0069-1 |url-status=live }}

File:A_rotated_scanning_electron_microscope_photograph_of_a_Tesla_valve_by_Forster_et_al._J_anona-2020-0014_fig_001.jpg

The Tesla valve is used in microfluidic applications and offers advantages such as scalability, durability, and ease of fabrication in a variety of materials. It is also used in macrofluidic applications and pulse jet engines. In 2021 Xiaomi announced that some of their mobile phones will be using loop liquid cooling technology. This technology uses a Tesla valve to make sure that the coolant flow is unidirectional. {{Cite web |title=Explained: How liquid cooling technology works in smartphone |url=https://timesofindia.indiatimes.com/gadgets-news/explained-how-liquid-cooling-technology-works-in-smartphones/articleshow/90228130.cms}}{{Cite web |title=Liquid cooling and Tesla valves are coming to smartphones |url=https://www.androidauthority.com/xiaomi-loop-liquidcool-heat-dissipation-technology-3054927/}}

File:Tesla_valve_principle.svg

One computational fluid dynamics simulation of Tesla valves with two and four segments showed that the flow resistance in the blocking (or reverse) direction was about 15 and 40 times greater, respectively, than the unimpeded (or forward) direction. This lends support to Tesla's patent assertion that in the valvular conduit in his diagram, a pressure ratio "approximating 200 can be obtained so that the device acts as a slightly leaking valve".

Steady flow experiments, including with the original design, however, show smaller ratios of the two resistances in the range of 2 to 4. It has also been shown that the device works better with pulsatile flows.

• Coandă effect
• Check valve
• Diode
• Labyrinth seal
• Static mixer
• Valve

{{reflist|refs=

{{Cite web|url=https://fluidpowerjournal.com/2013/10/teslas-conduit/|archive-url=https://web.archive.org/web/20170113033316/https://fluidpowerjournal.com/2013/10/teslas-conduit/|url-status=dead|archive-date=2017-01-13|title=Tesla's Valvular Conduit - Fluid Power Journal|date=2013-10-23|website=Fluid Power Journal|language=en-US|access-date=2017-01-13}}

{{cite journal|last1=Gamboa|first1=Adrian R.|last2=Morris|first2=Christopher J.|last3=Forster|first3=Fred K.|title=Improvements in Fixed-Valve Micropump Performance Through Shape Optimization of Valves|journal=Journal of Fluids Engineering|date=2005|volume=127|issue=2|pages=339|doi=10.1115/1.1891151|s2cid=55961879}}

{{cite book|last1=Deng|first1=Yongbo|last2=Liu|first2=Zhenyu|last3=Zhang|first3=Ping|title=2010 IEEE 23rd International Conference on Micro Electro Mechanical Systems (MEMS) |chapter=Optimization of no-moving part fluidic resistance microvalves with low reynolds number |pages=67–70|date=28 Jan 2010|doi=10.1109/MEMSYS.2010.5442565|chapter-url=https://www.researchgate.net/publication/224129251|isbn=978-1-4244-5761-8|s2cid=22740698|access-date=12 May 2021|archive-date=12 May 2021|archive-url=https://web.archive.org/web/20210512154220/https://www.researchgate.net/publication/224129251_Optimization_of_no-moving_part_fluidic_resistance_microvalves_with_low_Reynolds_number|url-status=live}}

{{cite journal|last1=Nguyen|first1=Quynh M.|last2=Abouezzi|first2=Joanna|last3=Ristroph|first3=Leif|journal= Nature Communications| title=Early turbulence and pulsatile flows enhance diodicity of Tesla's macrofluidic valve |issue =12 |pages=2884|date=17 May 2021|volume=12 |doi=10.1038/s41467-021-23009-y|pmid=34001882 |pmc=8128925 |doi-access=free|arxiv=2103.17222 |bibcode=2021NatCo..12.2884N }}

{{cite journal|last1=Nguyen|first1=Quynh M.|first2=Dean|last2=Huang|first3=Evan|last3=Dean|first4=Genievieve|last4=Romanelli|first5=Charlotte|last5=Meyer|last6=Ristroph|first6=Leif|title=Tesla's fluidic diode and the electronic-hydraulic analogy|journal= American Journal of Physics| volume = 89 |pages=393–402|date= Oct 2020|issue=4 |doi=10.1119/10.0003395|arxiv=2103.14813|s2cid=232401497 }}

{{cite web|title=Patent #: US001329559|url=http://pdfpiw.uspto.gov/.piw?PageNum=0&docid=01329559&IDKey=BD3AA70D843B%0D%0A&HomeUrl=http%3A%2F%2Fpatft.uspto.gov%2Fnetacgi%2Fnph-Parser%3FSect1%3DPTO1%2526Sect2%3DHITOFF%2526d%3DPALL%2526p%3D1%2526u%3D%25252Fnetahtml%25252FPTO%25252Fsrchnum.htm%2526r%3D1%2526f%3DG%2526l%3D50%2526s1%3D1329559.PN.%2526OS%3DPN%2F1329559%2526RS%3DPN%2F1329559|website=United States Patent and Trademark Office|publisher=Office of the Chief Communications Officer|accessdate=2 January 2017|archive-date=3 January 2017|archive-url=https://web.archive.org/web/20170103095151/http://pdfpiw.uspto.gov/.piw?PageNum=0&docid=01329559&IDKey=BD3AA70D843B%0D%0A&HomeUrl=http%3A%2F%2Fpatft.uspto.gov%2Fnetacgi%2Fnph-Parser%3FSect1%3DPTO1%26Sect2%3DHITOFF%26d%3DPALL%26p%3D1%26u%3D%252Fnetahtml%252FPTO%252Fsrchnum.htm%26r%3D1%26f%3DG%26l%3D50%26s1%3D1329559.PN.%26OS%3DPN%2F1329559%26RS%3DPN%2F1329559|url-status=live}}

{{cite journal|last1=de Vries|last2=Florea|last3=Homburg|last4=Frijns|title=Design and operation of a tesla-type valve for pulsating heat pipes|journal=International Journal of Heat and Mass Transfer|volume=105|pages=1–11|doi=10.1016/j.ijheatmasstransfer.2016.09.062|year=2017|doi-access=free}}

• "Simulation and Optimization of Tesla Valves", [http://www.nsti.org/procs/Nanotech2003v1/9/M72.05 T-Q Truong and N-T Nguyen, Nanotech 2003 Vol. 1 Technical Proceedings of the 2003 Nanotechnology Conference and Trade Show, Volume 1] {{ISBN|0-9728422-0-9}}

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• {{YouTube|tcV1EYSUQME|Tesla Valve Explained With Fire

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• {{YouTube|suIAo0EYwOE|Tesla Valve {{!}} The complete physics

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Category:Plumbing valves

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