Enjin haba

Dalam termodinamik dan kejuruteraan, enjin haba ialah sistem yang menukar haba kepada tenaga mekanikal, yang kemudiannya boleh digunakan untuk melakukan kerja mekanikal.^[1]^[2] Ia melakukan ini dengan membawa bahan kerja dari suhu keadaan yang lebih tinggi kepada suhu keadaan yang lebih rendah. Sumber haba menjana tenaga haba yang membawa bahan kerja ke keadaan suhu tinggi. Bahan kerja menjana kerja dalam badan kerja enjin sambil memindahkan haba ke sinki yang lebih sejuk sehingga ia mencapai keadaan suhu rendah. Semasa proses ini beberapa tenaga haba ditukar kepada kerja dengan mengeksploitasi sifat bahan kerja. Bahan kerja boleh menjadi mana-mana sistem dengan kapasiti haba bukan sifar, tetapi ia biasanya gas atau cecair. Semasa proses ini, sebahagian haba biasanya hilang ke persekitaran dan tidak ditukar kepada berfungsi. Juga, sesetengah tenaga tidak boleh digunakan kerana geseran dan seretan.

Rujukan sunting

^ Fundamentals of Classical Thermodynamics, 3rd ed. p. 159, (1985) by G. J. Van Wylen and R. E. Sonntag: "A heat engine may be defined as a device that operates in a thermodynamic cycle and does a certain amount of net positive work as a result of heat transfer from a high-temperature body and to a low-temperature body. Often the term heat engine is used in a broader sense to include all devices that produce work, either through heat transfer or combustion, even though the device does not operate in a thermodynamic cycle. The internal-combustion engine and the gas turbine are examples of such devices, and calling these heat engines is an acceptable use of the term."
^ Mechanical efficiency of heat engines, p. 1 (2007) by James R. Senf: "Heat engines are made to provide mechanical energy from thermal energy."

Bacaan lanjut sunting

Kroemer, Herbert; Kittel, Charles (1980). Thermal Physics (ed. 2nd). W. H. Freeman Company. ISBN 0-7167-1088-9.
Callen, Herbert B. (1985). Thermodynamics and an Introduction to Thermostatistics (ed. 2nd). John Wiley & Sons, Inc. ISBN 0-471-86256-8.
Robinson, Clark (1943). The Thermodynamics of Firearms. MaGraw-Hill Book Company Inc.

[1] Fundamentals of Classical Thermodynamics, 3rd ed. p. 159, (1985) by G. J. Van Wylen and R. E. Sonntag: "A heat engine may be defined as a device that operates in a thermodynamic cycle and does a certain amount of net positive work as a result of heat transfer from a high-temperature body and to a low-temperature body. Often the term heat engine is used in a broader sense to include all devices that produce work, either through heat transfer or combustion, even though the device does not operate in a thermodynamic cycle. The internal-combustion engine and the gas turbine are examples of such devices, and calling these heat engines is an acceptable use of the term."

[2] Mechanical efficiency of heat engines, p. 1 (2007) by James R. Senf: "Heat engines are made to provide mechanical energy from thermal energy."

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