Energy Conservation Engineering Laboratory

Toyohashi university of technology, Department of mechanical engineering

Research topics

Development of high-performance filtration system for insulating liquids

In order to decrease the failures of machines, to lengthen the life of oil and to decrease waste oil, it is essential for contaminants including submicrometer-sized ones to be removed from oil. An electrostatic oil filter can separate even submicrometer-sized contaminants from oil but its filtration speed is slow. Our laboratory has proposed a charge-injection type of electrostatic oil filter and has demonstrated that the filtration speed can be increased to a great or some degree by charge injection into oil. Research activities have been continuously done to find out an optimal configuration of the charge-injection type of electrostatic oil filter as well as that of conventional type one by experiment and numerical simulation. The load on an electrostatic oil filter can be reduced by removing coarse contaminants by e.g. a hydrocyclone. The research on a hydrocyclone suited for oil filtration is made. 

(Keywords: Filtration, Lubricating oil, Reuse, Oil saving, Electrostatic oil filter, Chare injection, Hydrocyclone, Coagulation)


Fundamental investigation and application of electrohydrodynamic (EHD) flow

・Study on EHD pumps

A flow caused by Coulomb force acting on excess electric charges in a liquid is called the ion drag flow, which is typical of electrohydrodynamic flows, and can be applied to pumps and actuators. The application of EHD phenomenon has recently been increased resulting from the development of the so-called functional fluids suited for the generation of EHD flow. In this research topic, fundamental characteristics of ion drag flow and its applications are investigated by experiment and numerical simulation.

(Keywords: Electrohydrodynamics, Ion drag, Pump, Actuator, Charge injection)

・Plasma Actuators

Plasma Actuators (PAs) induce flows by high-voltage (kv-) and high-frequency (kHz-) alternating voltage. The PA has many advantages compared with other flow control actuators, no moving parts; fast time response; low mass and easily attached curved surfaces. In this laboratory, we perform research on improvement of fluid-related machinery such as reducing aerodynamic noise using the PA. For effective control, the effects of the configurations and arrangements of the PA on the control are investigated. Moreover, based on the effective control by the PA, passive control by change of body shape or other controls such as blowing jets are also investigated.

(Key word: Plasma,Flow control,Aerodynamic noise,Actuator)

Dynamic behaviors of friction and their mathematical model

If a mathematical model that can simulate the dynamic behaviors of friction observed in mechanical systems is constructed, it will be helpful in predicting the motions of the mechanical systems accurately. Our laboratory has proposed a new model, called the modified LuGre model into which lubricant film dynamics is incorporated and has been shown that the model can simulate the dynamic friction behaviors of hydraulic actuators with a relatively good accuracy. Dynamic friction behaviors of other actuators are examined and the application of the modified LuGre model to other mechanical systems is undertaken.

(Keywords:Dynamic friction behavior, Friction model, LuGre model, Lubricant film, Actuator)


Aerodynamic noise generated from high-speed transports and fluid equipments

Aerodynamic noise increases in proportional to the high power of velocity. So, the noise is a sever problem for high-speed transport vehicles or flow-related machinery. For example, intense tonal sound radiates from cavity flow and flow around a cascade of flat plates, where the feedback loop due to fluid-acoustic interactions occurs. To clarify the mechanism of acoustic radiation and establish the methodologies for noise reduction, we perform wind tunnel experiments and aeroacoustic direct numerical simulation (AADNS). Also, to establish the prediction method of aerodynamic noise, decoupled simulations consisting of acoustic and flow simulations are focused on.
○Cavity tone
○Control of aerodynamic noise by plasma actuators
○Aerodynamic noise from flows around a cascade of flat plates with acoustic resonance
○Tonal sound from automobiles parts such as bonnet, door mirror and sunroof
○Decoupled simulations based on Lighthill analogy
(Keywords: Aeroacoustics, Control, Direct aeroacoustic simulation, Wind tunnel experiments)


Study on thermal energy devices

・Thermoacoustic devices

Devices in which heat-sound interactions play an important role are known as thermoacoustic systems. Sound spontaneously occurs by adding temperature difference in stacked mesh. The refrigerator by usage of exhaust heat based on the thermoacoustic phenomena is investigated. To improve the efficiency of this device, the flow and acoustic fields in the thermoacoustic engine are clarified.

(key word: Thermoacoustic phenomena, Refrigerator,Usage of exhaust heat)


・Study on investigation of two-phase thermal hydraulics in a capillary evaporator of a loop heat pipe for practical application

On aerospace engineering, automotive, electronic equipment such as PC, rapid increase in heat generation density associated with downsizing and efficiency enhancement has become a problem, so the development of high-performance thermal control device is necessary. In particular, capability for energy and space saving is required. Therefore, we are focusing on loop heat pipes (LHPs), which is a two-phase heat transport device using no electric power. To establish the technology, we make basic and applied research with experimental and analytical approach such as the LHP of design and manufacture, performance test under simulated space environment, non-steady-state analysis, performance enhancement by the porous body shape.
A porous structure called as a wick is placed in the evaporator of the LHP in order to generate a capillary force as the driving force. So, physics of vapor-liquid two-phase flow in the porous structure with a phase change is dominant. Since the physical phenomena of the evaporator is not understood well, the design method such as wick shape has not been established. Therefore, we investigate the physical phenomena by three-dimensional analysis and visualization experiment then, to build optimum design theory based on the thermal-hydraulics is out goal.

(Keywords: Loop Heat Pipe, Liquid-Vapor Two-Phase Flow, Pore Network Model, Capillary Force, Flow in a porous structure, percolation)

Address: 1-1, Hibarigaoka, Tenpaku-cho, Toyohashi, Aichi, 441-8580, Japan
Department of Mechanical Engineering, Toyohashi University of Technology
Prof. Yanada room   | Building D, D-309
  E-mail | Following [yanada], []
Dr. Yokoyama room   | Building D, D-306
  E-mail | Following [h-yokoyama], []
Dr. Nishikawara and student room   | Building D2,D2-202
  E-mail | Following [nishikawara], []


Toyohashi University of Technology   Department of Mechanical Engineering  


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