scholarly journals Improving Heat-Engine Performance via High-Temperature Recharge

2020 ◽  
Author(s):  
Jack Denur
Keyword(s):  
High Temperature ◽  
Heat Engine ◽  
Engine Performance

Micro Thermal Engines: Is There Any Room at the Bottom?

1999 ◽  
Author(s):  
Richard B. Peterson
Keyword(s):  
Heat Transfer ◽  
Scaling Laws ◽  
Critical Role ◽  
Heat Engine ◽  
Engine Performance ◽  
Characteristic Size ◽  
Operating Efficiency ◽  
Simple Scaling ◽  
Small Structure ◽  
Micro Heat Engine

Abstract Richard P. Feynman introduced the field of microscale and nanoscale engineering in 1959 by giving a talk on how to make things very small. Feynman’s premise was that no fundamental physical laws limit the size of a machine down to the microscopic level. Is this true for all types of machines? Are micro thermal devices fundamentally different than mechanically-based machines with respect to their scaling laws? This paper demonstrates that micro thermal engines do indeed suffer serious performance degradation as their characteristic size is reduced. A micro thermal engine, and more generally, any thermally-based micro device, depends on establishing a temperature difference between two regions within a small structure. In this paper, the performance of a micro thermal engine is explored as a function of the characteristic length parameter, L. In the development, the important features of thermal engines are discussed in the context of developing simple scaling laws predicting the dependency of the operating efficiency on L. After this is accomplished, a general model is derived for a heat engine operating between two temperature reservoirs and having both intrinsic and extrinsic sources of irreversibility, i.e. thermal conductances and heat leakage paths for the heat flow. With this model and typical numerical values for the conductances, micro heat engine performance is predicted as the characteristic size is reduced. This paper demonstrates that under at least one particular formulation of the problem, there may indeed be some room at the bottom. However, heat transfer does play a critical role in determining micro engine performance and depending on how the heat transfer through the engine is modeled, vanishingly small efficiencies can result as the characteristic engine size goes to zero.

Experimental Exploration of a Small Scale Pneumatically Pumped Thermal Storage System

2016 ◽  
Author(s):  
Inri Rodriguez ◽  
Jesus Cerda ◽  
Daniel S. Codd
Keyword(s):  
High Temperature ◽  
Storage Tank ◽  
Pulse Width Modulation ◽  
Low Cost ◽  
Storage System ◽  
Heat Engine ◽  
Thermal Storage ◽  
Heat Transfer Fluid ◽  
Small Scale ◽  
Constant Frequency

A prototype water-glycerol two tank storage system was designed to simulate the fluidic properties of a high temperature molten salt system while allowing for room temperature testing of a low cost, small scale pneumatically pumped thermal storage system for use in concentrated solar power (CSP) applications. Pressurized air is metered into a primary heat transfer fluid (HTF) storage tank; the airflow displaces the HTF through a 3D printed prototype thermoplate receiver and into a secondary storage tank to be dispatched in order to drive a heat engine during peak demand times. A microcontroller was programmed to use pulse-width modulation (PWM) to regulate air flow via an air solenoid. At a constant frequency of 10Hz, it was found that the lowest pressure drops and the slowest flowrates across the receiver occurred at low duty cycles of 15% and 20% and low inlet air pressures of 124 and 207 kPa. However, the data also suggested the possibility of slug flow. Replacement equipment and design modifications are suggested for further analysis and high temperature experiments. Nevertheless, testing demonstrated the feasibility of pneumatic pumping for small systems.

Modifikasi Oil Breather System Dengan Selang High Temperature Pada Yamaha MIO-J Tahun 2012

2019 ◽  
Vol 9 (1) ◽  
pp. 12-20
Author(s):  
Askan ◽  
Muhammad Fakhrurozi
Keyword(s):  
High Temperature ◽  
Everyday Life ◽  
Engine Performance ◽  
Heat Temperature ◽  
Vehicle Engine ◽  
Oil Pump ◽  
The Right ◽  
Motorized Vehicles

Motorized vehicles are one of the most widely used means of transportation in everyday life by the community. Engine performance is supported by the presence of an engine that complements the vehicle's performance due to the engine as a lubricant in motorized vehicles. In motorized vehicles, it is often found that engine problems are quickly hot when used by drivers when traveling long distances and even when stuck in traffic. To overcome this problem, an Oil Breather System will be added to the vehicle by punching a hole on the right side of the engine and planting a nipple for the hose holder Oil Breather System. From that point on, the oil will flow quickly directly from the oil pump. The oil is then passed on the hose to the Oil Breather System. From there the oil is cooled by gusts of wind received by the Oil Breather System and proceed to the Oil Breather System hole. Therefore, the Oil Breather System was installed in motorized vehicles. With the installation of the Oil Breather System in the Cover Valve section, the Cover driven chain air heat temperature on the 2012 Yamaha Mio-J vehicle engine can be reduced by a temperature of 5 ° C. This research will continue for other types of vehicles.

Combustor Flame Sensor With High Temperature Electronics

1995 ◽  
Author(s):  
Wm. Michael Glasheen ◽  
Deidre E. Cusack ◽  
Helmar R. Steglich
Keyword(s):  
High Temperature ◽  
Dynamic Range ◽  
Engine Performance ◽  
Sensor Data ◽  
Electronic Components ◽  
Detector Performance ◽  
Turbine Engine ◽  
High Temperature Electronics ◽  
Deep Ultraviolet ◽  
High Temperature Electronic

A high temperature solid state turbine flame sensor has been developed and is being tested for eventual use as a combustor performance sensor. It directly senses only the flame deep ultraviolet without any response to hot component infrared energy (> 700 nanometers); the dynamic range is large; and the response time is fast enough for combustor control, i.e., less than 200 milliseconds. The sensor electronics operate up to 250°C and some detector performance data has been taken as high as 540°C as described by Cusack et al (1994). The design uses recently available SiC electronic components, other components specially tested for the application, and proprietary techniques of electronic component packaging. Specific experience in packaging turbine engine optical and temperature sensors is necessary for this unique high temperature electronic technology. A test program for discrete components indicates what elements are available for this temperature range and prototype sensor data from both laboratory qualification tests and engine performance tests verify the design.

scholarly journals Experimental Investigation of High Temperature-Resistant Inductive Sensor for Blade Tip Clearance Measurement

Sensors ◽  
2018 ◽  
Vol 19 (1) ◽  
pp. 61 ◽  
Author(s):  
Ziyu Zhao ◽  
Zhenxia Liu ◽  
Yaguo Lyu ◽  
Yajun Gao
Keyword(s):  
High Temperature ◽  
Engine Performance ◽  
Response Speed ◽  
Tip Clearance ◽  
Effect Of Temperature ◽  
Inductive Sensor ◽  
Sensing Range ◽  
Coil Inductance ◽  
Contact Distance ◽  
Planar Coil

Turbine tip clearance of aero-engine is important to engine performance. Proper control of rotor tip clearance contributes to engine efficiency improvement and fuel consumption reduction. Therefore, accurate tip clearance measurement is essential. The inductive measurement method is one of the non-contact distance measurement methods, which has the characteristics of high sensitivity, fast response speed and strong anti-interference ability. Based on the principle of inductive sensor measuring tip clearance, the ambient temperature change will cause the material electromagnetic performance change for the conductivity and permeability varies with temperature. The calibration experiment was conducted to obtain the sensor resolution and sensing range. The effect of temperature on sensor parameters was extracted from high temperature experiment data. Results show the resolution of planar coil made of platinum wire can be 10 μm and the maximum sensing range can reach 5 mm. At temperature from 500 ℃ to 1100 ℃, coil inductance almost does not change with temperature while coil resistance varies exponentially with temperature, that means the coil inductance variation can reflect the tip clearance change and resistance can indicate the measuring temperature.

Modifikasi Oil Breather System Dengan Selang High Temperature Pada Yamaha MIO-J Tahun 2012

2018 ◽  
Vol 9 (1) ◽  
pp. 12-20
Author(s):  
Askan Askan ◽  
Muhammad Fakhrurozi
Keyword(s):  
High Temperature ◽  
Everyday Life ◽  
Engine Performance ◽  
Heat Temperature ◽  
Vehicle Engine ◽  
Oil Pump ◽  
The Right ◽  
Motorized Vehicles

Motorized vehicles are one of the most widely used means of transportation in everyday life by the community. Engine performance is supported by the presence of an engine that complements the vehicle's performance due to the engine as a lubricant in motorized vehicles. In motorized vehicles, it is often found that engine problems are quickly hot when used by drivers when traveling long distances and even when stuck in traffic. To overcome this problem, an Oil Breather System will be added to the vehicle by punching a hole on the right side of the engine and planting a nipple for the hose holder Oil Breather System. From that point on, the oil will flow quickly directly from the oil pump. The oil is then passed on the hose to the Oil Breather System. From there the oil is cooled by gusts of wind received by the Oil Breather System and proceed to the Oil Breather System hole. Therefore, the Oil Breather System was installed in motorized vehicles. With the installation of the Oil Breather System in the Cover Valve section, the Cover driven chain air heat temperature on the 2012 Yamaha Mio-J vehicle engine can be reduced by a temperature of 5 ° C. This research will continue for other types of vehicles.

Effects of Thermal Cycling on Elastomers in High Temperature Coolant

2010 ◽  
Author(s):  
Daniel L. Hertz
Keyword(s):  
High Temperature ◽  
Thermal Cycling ◽  
Cooling System ◽  
Engine Performance ◽  
Test Methods ◽  
Standard Test ◽  
Radial Deformation ◽  
Seal Design ◽  
Vulcanized Rubber ◽  
Before And After

In the past ten years diesel engine performance has significantly increased in terms of kilowatts/litre (kW/L). These higher power density outputs create higher thermal loads on the cooling system and associated seals. While compatibility of elastomers in high temperature coolants has been studied and reported, the inevitable impact of thermal cycling on these elastomers is not well documented. This study examines the effects of thermal cycling in three general coolant categories on three different elastomers commonly considered for sealing hot engine coolants. The elastomers, by ASTM D1418 designation, are HNBR, FKM Type 2, and FEPM. The coolants are an organic acid technology (OAT) coolant, a propylene glycol premix coolant, and a corrosion inhibited de-ionized water. Normal service applications are characterized by an indefinite number of shutdowns and startups. Testing was designed to simulate such service. Aging periods incorporated ongoing 24 hour cycles: a 16 hour period to heat up and operate at 150°C, and an 8 hour period to cool off to ambient. O-rings, a common seal design, were subject to axial and radial deformation during testing. The o-rings’ sealing attributes were examined after four, ten, twenty, and forty cycles. Elastomeric properties were evaluated, before and after cyclical aging, in accordance with ASTM D1414-94 (“Standard Test Methods for Rubber O-rings”) and D412-06a (“Standard Test Methods for Vulcanized Rubber … - Tension”). Compressive stress relaxation (CSR) was evaluated using an in-house procedure, comporting with ASTM D6147-94.

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