The pictures show one of the several species of passion flower / passion fruit. It is difficult to identify the species by pictures alone. It could be either
Passiflora foetida (Stinking passion flower, Krishna Kamal, Kaurav Pandav flower) as written by Rachuri Achar ji or
Pasiflora edulis (Passion Fruit, mamtaphala, amlaphalaas) as written by Chandrakant Bhoslay ji. Both the species are native to the South American continent and introduced in India after the European contact in the 16th century. Therefore, passion flower did not have any Sanskrit name at least till 1950s. Both species are cultivated in India for their medicinal importance. They have naturalised in some places. An the encyclopedia of medicinal plants 'Vanaushadhi Chandrodaya' वनौषधि चंद्रोदय published around 1950 lists Sanskrit names of hundreds of plants but gives only Tamil, Telugu and Malayalam names of passion flower. Since then, the flowers have been given various names in Indian languages based on local fancy, e.g. jhumak lata झुमक लता, ghadi phool घडी फूल, rakhi phool. राखी फूल, Krishna Kamal कृष्ण कमल, Kaurav Pandav flower कौरव पांडव फूल. There is an interesting explanation to its supposedly Sanskrit names -- Krishna Kamal, Kaurav Pandav flower). According to a web site
https://www.flickr.com/photos/76955614@N08/6908447249"there are (apparently) a 100 of those White Petals - one for each of the Kauravas, and 5 of the green ones in the centre - one for each of the Pandavas. The green bulb in the centre symbolises the Pandava queen Draupadi, and the three filaments are for the holy trinity of Brahma-Vishnu-Shiv. AND the white radial in the centre is the Sudarshan chakra of Lord Krishna."
Chandrakant Bhoslay ji, you have written, "
It's not a flower but part of fruit."Sorry. The pictures show complete flowers before formation of the fruit. The ovary of flower develops into fruit after fertilization. The fruit of passion flower has usual round shape as in other plants.
Rajendra Gupta