Determination of the Near Wall Flow of a Multi-Stage Tesla Diode Using PIV and PTV

Particle image velocimetry (PIV) and particle tracking velocimetry (PTV) are two popular methods to measure the velocity in complex geometries such as the Tesla valve. This paper provides an investigation on the application of a tessellation meshing method for interpolating non-uniform velocity vectors calculated using PTV. The procedure to apply this method containing mask generation and mesh study is described. The results are compared to the PIV results particularly where the near wall results are important. The result of the flow field calculated by the application of the tessellation method on the PTV results are presented for a two-stage Tesla valve operated in the range of Re = 100 to 600 both in forward and reverse configuration.

Shark spiral intestines may operate as Tesla valves

Looking to nature for inspiration has led to many diverse technological advances. The spiral valve intestine of sharks has provided the opportunity to observe the efficiency of different valve systems. It is supposed that the spiral intestine present in sharks, skates and rays slows the transit rate of digesta through the gut and provides increased surface area for the absorption of nutrients. In this investigation, we use a novel technique—creating three-dimensional reconstructions from CT scans of spiral intestines—to describe the morphology of the spiral intestine of at least one species from 22 different shark families. We discuss the morphological data in an evolutionary, dietary and functional context. The evolutionary analyses suggest that the columnar morphology is the ancestral form of the spiral intestine. Dietary analyses reveal no correlation between diet type and spiral intestine morphology. Flow rate was slowed significantly more when the two funnel-shaped spiral intestines were subjected to flow in the posterior to anterior direction, indicating their success at producing unidirectional flow, similar to a Tesla valve. These data are available to generate additional three-dimensional morphometrics, create computational models of the intestine, as well as to further explore the function of the gastrointestinal tract of sharks in structural and physiological contexts.

Valveless Piezoelectric Pump with Reverse Diversion Channel

In order to reduce backflow and improve output performance, a valveless piezoelectric pump with a reverse diversion channel was produced. The channel was designed based on the structure of the Tesla valve, which has no moving parts and can produce a high-pressure drop during reverse flow. Therefore, this special flowing channel can reduce the backflow of a valveless piezoelectric pump, which has the characteristic of one-way conduction. This work first revealed the relationship between the main structural parameters of the Tesla valve and the kinetic energy difference of liquid. Then, by using simulation software, the structure was verified to have the characteristics of effective suppression of the backflow of valveless piezoelectric pumps. Through setting multiple simulations, some important parameters that include the optimal height between the straight channels (H), the optimal angle (α) between the straight channel and the inclined channel, as well as the optimal radius (R) of the channel were confirmed. Finally, a series of prototypes were fabricated to test the output performance of this valveless piezoelectric pump. Comparing the experimental results, the optimal parameters of the Tesla valve were determined. The results suggest that when the parameters of the Tesla valve were H = 8 mm, α = 30°, and R = 3.4 mm, the output performance of this piezoelectric pump became best, which had a maximum flow rate of 79.26 mL/min with a piezoelectric actuator diameter of 35 mm, an applied voltage of 350 Vp-p, and a frequency of 28 Hz. The effect of this structure in reducing the return flow can be applied to fields such as agricultural irrigation.

An Experimental Investigation of Flow Phenomena in a Multi-Stage Micro Tesla Valve

The Tesla-diode valve, with no moving parts, allows restricted flow in one direction. It has many potential applications in different industrial situations. Despite the application of the valve and the importance of the effect of flow phenomena on the Tesla valve's performance, very few studies have experimentally investigated the motion of flow within the Tesla valve. This study aims to contribute to this growing area of research on the performance of Tesla valves by demonstrating the flow phenomena and the flow conditions needed to be used in numerical studies. In this work, the effect of direction of the flow and Reynolds number on the flow phenomena generated in a Tesla-diode valve is studied. Particle shadowgraph velocimetry (PSV) is utilized to investigate and visualize the velocity field. The results of this study confirm some of the phenomena that has been observed using numerical simulations. It also highlights the flow phenomena leading to an increase in the diodicity by an increase in the number of Tesla loops in the valve. An important observation often ignored in numerical simulation is the presence of unsteady behavior and vortex shedding for higher Reynolds number flows.

Design and Optimization of Strength type Negative Pressure Suction Force Pluck Port based on Tesla Valve

An apple pluck port based on negative pressure suction force can realize contactless apple plucking and also reduce possible damage to the apple. Accordingly, in this study, a strength type pneumatic pluck port was designed on the basis of a Tesla valve. First, a low air pressure block for mechanization of the Tesla valve structure at the intersection between the main and curved air passageway was theoretically modelled and analyzed. Then, the air pressure and the flow speed distribution were analyzed for three different types of structure parameters under various distances of the Tesla pluck port from the apple; on the basis of a fluent simulation, the maximum pressure difference at both sides of the apple was also simulated. Finally, the structure parameters under an optimal negative pressure field according to the simulation analysis were proposed, and a manufactured experimental test was conducted to compare the results with the simulation. The simulation and experimental data prove that when the included angle between the main and curved air passageway of the Tesla pluck port is lower than 45°, the low air pressure block at the intersection between the main and curved air passageway of the Tesla valve affects the flow of the pluck port and extends the length of the low air pressure block. The Tesla pluck port guarantees a flow in the pipe when the pipe port diameter is 10–15 mm larger than the apple diameter, ensuring the negative strengthening effect of the Tesla pluck port. The experiment proves that the Tesla pluck port designed in this study exhibits a better negative pressure strengthening effect than that achieved via previously existing methods, which can strengthen the plucking effect.