Search results

Filters

  • Journals
  • Authors
  • Keywords
  • Date
  • Type

Search results

Number of results: 7
items per page: 25 50 75
Sort by:
Download PDF Download RIS Download Bibtex

Abstract

The potential applications of loop heat pipes (LHPs) are the nuclear power space systems, fuel cell thermal management systems, waste heat recovery systems, medium temperature electronic systems, medium temperature military systems, among others. Such applications usually operate in temperature ranges between 500–700 K, hence it is necessary to develop an LHP system that will meet this requirement. Such a thermal management device require to meet various technical problems and challenges currently existing in the development of LHP working in medium temperatures, including: (1) selection of appropriate working fluid; (2) selection of appropriate LHP construction material; (3) construction of suitable test rig capable of testing at elevated temperatures; (4) development of new testing methods. Currently, there are no proven working fluids that can be used in LHPs in medium temperature ranges. Water can be applicable only at temperatures up to 570 K. Caesium can be applicable at temperatures above 670 K. Organic fluids usually tend to generate non-condensable gasses and/or decompose at elevated temperatures and their viscosity dramatically increases. For halides, most of them are very reactive or toxic and their full property data are not available or the majority of the physical properties are predicted, also live tests and their environmental impact data are not adequate. As for casing/LHP construction material, there are no full chemical compatibility tables with most of the medium temperature working fluids and the reactivity of fluids significantly limits the potential materials. Also, testing such an LHP is an endeavour as the reactivity of medium temperature fluids and the use of obscure metals create new challenges. Altogether creates multiple challenges in the development, testing, handling and operating of LHP in the medium temperature range.
Go to article

Bibliography

[1] Zohuri B.: Heat Pipe Design and Technology. Modern Applications for Practical Thermal Management (2nd Edn.). Springer, 2016.
[2] Zhang Y. (Ed.): Heat Pipes: Design, Applications and Technology. Nova, 2018.
[3] Anderson W.G., Bland J.J., Fershtater Y., Goncharov K.A., Nikitkin M., Juhasz A.: High-temperature loop heat pipes. IECEC AP-18, ASME 1995.
[4] Anderson W.G., Rosenfeld J.H., Angirasa D., Mi Y.: Evaluation of heat pipe working fluids in the temperature range 450 to 700 K. AIP Conf. Proc. 699(2004), 20.
[5] Anderson W.G., Bienert W.: Loop heat pipe radiator trade study for the 300– 550 K temperature range. AIP Conf. Proc. 746(2005), 946.
[6] Anderson W.G.: Intermediate temperature fluids for heat pipes and loop heat pipes. In: Proc. 5th Int. Energy Conversion Engineering Conf. Exhib. (IECEC), 25–27 June 2007, AIAA 2007–4836.
[7] Faghri A., Buchko M., Cao Y.: A study of high-temperature heat pipes with multiple heat sources and sinks: Part I – Experimental methodology and frozen startup profiles. J. Heat Transf. 113(1991), 4, 1003–1009.
[8] Faghri A., Buchko M., Cao Y.: A study of high-temperature heat pipes with multiple heat sources and sinks: Part II – Analysis of continuum transient and steadystate experimental data with numerical predictions. J. Heat Transf. 113(1991), 4, 1010–1016.
[9] https://www.1-act.com/merit-number-and-fluid-selection/ (accessed 10 Sept. 2021).
[10] NIST Reference Fluid Thermodynamic and Transport Properties Database (REFPROP), Version 10. https://www.nist.gov/srd/refprop/ (accessed 10 Sept. 2021).
[11] Blauciak K., Szymanski P., Mikielewicz D.: The influence of loop heat pipe evaporator porous structure parameters and charge on its effectiveness for ethanol and water as working fluids. Materials 14(2021), 7029.
[12] Nikitkin M.N., Bienert W.B., Goncharov K.A.: Non condensable gases and loop heat pipe operation. SAE Tech. Pap. 981584. In: Proc. 28th Int. Conf. on Environmental Systems, 1998.
[13] Wrenn K.R., Wolf D., Kroliczek E.J.: Effect of non-condensible gas and evaporator mass on loop heat pipe performance. SAE Tech. Pap. 2000-01-2409. In: Proc. 30th Int. Conf. on Environmental Systems, 603–614, 2000.
[14] Ishikawa H., Ogushi T., Nomura T., Noda H., Kawasaki H., Yabe T.: Heat transfer characteristics of a reservoir embedded loop heat pipe (2nd report, influence of noncondensable gas on heat transfer characteristics). Heat Transf. Asian Res. 36(2007), 8, 459–473.
[15] Singh R., Akbarzadeh A., Mochizuki M.: Operational characteristics of the miniature loop heat pipe with non-condensable gases. Int. J. Heat Mass Tran. 53(2010), 17–18, 3471–3482.
[16] He J., Lin G., Bai L., Miao J., Zhang H.: Effect of non-condensable gas on the operation of a loop heat pipe. Int. J. Heat Mass Tran. 70(2014), 449–462.
[17] Prado-Montes P.: Development of an elevated temperature loop heat pipe for space applications and investigation of non-condensable gas impact on its performance. PhD thesis, Polytechnic University of Madrid, Madrid 2014.
[18] Devarakonda A., Xiong D., Beach E.D.: Intermediate temperature water heat pipe tests. AIP Conf. Proc. 746(2005), 158.
[19] Mishkinis D., Prado P., Sanz R., Radkov A., Torres A., Tjiptajardja T.: Loop heat pipe working fluids for intermediate temperature range: from –40°C to +125°C. In: Proc. 1st. Int. Conf. on Heat Pipes for Space Applications, Moscow, Sept. 2009.
[20] Mikielewicz D, Błauciak K.: Investigation of the influence of capilary effect on operation of the loop heat pipe. Arch. Thermodyn. 35(2014), 3, 59–80.
Go to article

Authors and Affiliations

Paweł Szymański
1
Dariusz Mikielewicz
1

  1. Gdansk University of Technology, Faculty of Mechanical Engineering and Ship Technology, Narutowicza 11/12,80-233 Gdansk, Poland
Download PDF Download RIS Download Bibtex

Abstract

The evaporation temperature is regarded as one of the major parameters influencing the organic Rankine cycle (ORC) efficiency. Majority of contributions in literature for ORC cycle analyses treat the heat source as if it had an infinite heat capacity. Such analyses are not valuable as the resulting temperature drops of the heat source needs to be small. That leads to the fact that the heat source is not well explored and in the case of waste heat utilization it can prove the poor economics of the ORC. In the present study cooperation of the ORC cycle with the heat source available as a single phase or phase changing fluids is considered. The analytical heat balance models have been developed, which enable in a simple way calculation of heating fluid temperature variation as well as the ratio of flow rates of heating and working fluids in ORC cycle. The developed analytical expressions enable also calculation of the outlet temperature of the heating fluid.

Go to article

Authors and Affiliations

Dariusz Mikielewicz
Jarosław Mikielewicz
Download PDF Download RIS Download Bibtex

Abstract

The given article is an analysis of Władysław Wężyk’s Travels to the ancient world taking into consideration the most important problems and components of the 19th century Romantic worldview. Particular attention will be paid to the great Romantic themes such as folklore, art, music, spontaneous literary works and concepts of new humanity. Wężyk’s memoir reveals his openness towards the Other and the understanding of foreign cultures which is by far the most important feature of a Romantic intellectual.

Go to article

Authors and Affiliations

Monika Janota
Download PDF Download RIS Download Bibtex

Abstract

The authors attempted to present the state of disputes regarding the delimitation of marine areas based on a discussion of the practices of countries in the East China Sea and the Sea of Japan region. The authors describe the disputes regarding the islands of Senaku (Diaoyu) between both China and Taiwan and Japan and those over the Dokdo (Takeshima) archipelago between the Republic of Korea and Japan. There are many similarities between these two marine territorial disputes. The core of the disputes is land that is devoid of significant economic importance. Due to this, these areas were not previously of interest to coastal countries. They came to the forefront when their location facilitated determining exclusive economic zones. This intensified when evidence of crude oil and natural gas resources was detected in these areas. Tensions eased when geological reports revealed that initial estimates were overly optimistic. The fundamental cause of disputes over archipelagos is that they can be used to determine exclusive economic zones. The problem is compounded when the politicians of Eastern Asia incite historical remembrance. This is especially evident in the cases of Japan, the Republic of Korea, Taiwan, and China, whose governments are, to some extent, hostages of ultra-nationalistic factions.

Go to article

Authors and Affiliations

Andrzej Makowski
ORCID: ORCID
Krzysztof Kubiak
Download PDF Download RIS Download Bibtex

Abstract

Constantly increasing prevalence of allergic diseases determines the attempts to elaborate the therapeutic strategies activating immune tolerance to particular allergen. Our current research focuses on the antigen-specifi c action of CD8+ suppressor T (Ts) lymphocytes induced in mice by intravenous administration of a high dose of haptenated syngeneic erythrocytes. While the regulatory activity of Ts cells mediated by exosome-delivered miRNA-150 is well defi ned, the mechanism of their induction remained unclear. Th erefore, the current studies investigated the immune eff ects induced in mice by intravenous administration of contact allergens coupled to syngeneic erythrocytes. In mouse models of hapten-induced contact hypersensitivity (CHS) and delayed-type hypersensitivity to ovalbumin, we have shown that intravenous administration of hapten-coupled erythrocytes failed to induce CHS effector cells. Moreover, hapten-induced CHS reaction occurred to be suppressed in mice intravenously administered with syngeneic erythrocytes coupled with protein allergen. Finally, we have demonstrated that intravenously administered allergen induces immune tolerance only when bound to syngeneic erythrocytes, proving that intravenously delivered allergens are deprived of their immunizing properties when coupled with membrane of self cells. Altogether, our current studies suggest that alteration of self cell membrane by allergen binding is enough to induce Ts cell-mediated immune tolerance to nonpathogenic agents, which express a great translational potential in such conditions as allergies and hypersensitivity-related autoimmune disorders.

Go to article

Authors and Affiliations

Katarzyna Nazimek
Magdalena Wąsik
Philip W. Askenase
Krzysztof Bryniarski
Download PDF Download RIS Download Bibtex

Abstract

In the recent years structural health monitoring (SHM) has gathered spectacular attention in civil engineering applications. Application of such composites enable to improve the safety and performance of structures. Recent advances in nanotechnology have led to development of new family of sensors – self-sensing materials. These materials enable to create the so-called “smart concrete” exhibiting self-sensing ability. Application of selfsensing materials in cement-based materials enables to detect their own state of strain or stress reflected as a change in their electrical properties. The variation of strain or stress is associated with the variation in material’s electrical characteristics, such as resistance or impedance. Therefore, it is possible to efficiently detect and localize crack formation and propagation in selected concrete element. This review is devoted to present contemporary developments in application of nanomaterials in self-sensing cement-based composites and future directions in the field of smart structures.

Go to article

Authors and Affiliations

E. Horszczaruk
P. Sikora
P. Łukowski

This page uses 'cookies'. Learn more